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RSK-held areas in January 1995, and their proposed status according to the Z-4 Plan:
  Autonomous region within Croatia
  Revert to full Croatian control in two years
  Revert to full Croatian control immediately

The Z-4 Plan was a proposed basis for negotiations to end the Croatian War of Independence with a political settlement. It was drafted by Peter W. Galbraith, Leonid Kerestedjiants and Geert-Hinrich Ahrens on behalf of a mini-Contact Group comprising United Nations envoys and diplomats from the United States, Russia and the European Union. The co-chairs of the International Conference on the Former Yugoslavia, David Owen and Thorvald Stoltenberg, were closely involved in the political process surrounding the plan. The document was prepared in the final months of 1994 and early 1995 before being presented to Croatian President Franjo Tuđman and the leaders of the self-declared Republic of Serbian Krajina (RSK) on 30 January 1995. Tuđman was displeased with the proposal, but accepted it as a basis for further negotiations. However, the RSK authorities even refused to receive the document before UNPROFOR mandate status was resolved. According to later reactions, RSK leadership was not satisfied with the plan.

Three more attempts to revive the plan were made after Operation Flash in early May, when Croatia captured a portion of western Slavonia previously controlled by the RSK. The first initiative, that began later that month, failed because the RSK demanded that the Croatian forces pull back from western Slavonia (which Croatia declined to do). The second attempt failed simply because neither party wanted to negotiate. The final round of negotiations where the Z-4 Plan was proposed by international diplomats occurred in early August, when a major Croatian attack against the RSK seemed imminent. This time RSK leadership seemed more willing to negotiate based on Z-4 plan, but Croatia presented its own demands (including immediate replacement of the RSK with a Croatian civilian government), which were refused. On 4 August, Croatia launched Operation Storm, defeated the RSK and effectively ended the political process which led to the creation of the Z-4 Plan.

Elements of the plan made their way into two proposals on resolving the Kosovo crisis: in 1999 (during the Kosovo War) and in 2005 as a part of the Kosovo status process. Neither was accepted by the parties to that conflict.

Background

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Main article: Croatian War of Independence

In August 1990 an insurgency known as the Log Revolution took place in Croatia, centred on the predominantly Serb-populated areas of the Dalmatian hinterland around the city of Knin,[1] parts of the Lika, Kordun, and Banovina regions, and settlements in eastern Croatia with significant Serb populations.[2] These areas were subsequently named the Republic of Serbian Krajina (RSK) and, after the RSK declared its intention to unite with Serbia, the Government of Croatia declared the RSK a breakaway state.[3] By March 1991 the conflict escalated, resulting in the Croatian War of Independence.[4] In June 1991, Croatia declared its independence as Yugoslavia disintegrated.[5] A three-month moratorium on Croatia and the RSK's declarations followed,[6] after which their decisions were implemented on 8 October.[7]

Since the Yugoslav People's Army (JNA) increasingly supported the RSK and the Croatian Police were unable to cope with the situation, the Croatian National Guard (ZNG) was formed in May 1991. The ZNG was renamed the Croatian Army (HV) in November.[8] The establishment of the Croatian military was hampered by a September UN arms embargo.[9] The final months of 1991 saw JNA advances and the fiercest fighting of the war, culminating in the Siege of Dubrovnik[10] and the Battle of Vukovar.[11] In November a ceasefire was negotiated pending a political settlement (which became known as the Vance plan),[12] and it was implemented in early January 1992.[13] The ceasefire collapsed in January 1993 when the HV launched Operation Maslenica, and small-scale clashes continued for more than a year. On 16 March 1994, Russian envoy Vitaly Churkin brokered negotiations between Croatia and the RSK which produced a new ceasefire on 30 March. Further negotiations produced agreements on reopening a section of the Zagreb–Belgrade motorway (crossing the RSK-held part of western Slavonia, the Adria oil pipeline and several water-supply lines) by the end of 1994.[14]

Development

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Creation

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The Z-4 Plan was drafted by United States ambassador to Croatia Peter W. Galbraith, Russian ambassador to Croatia Leonid Kerestedjiants and German diplomat Geert-Hinrich Ahrens, representing the European Union (EU) in a "mini-Contact Group".[15] The Z in the plan's name stood for Zagreb (Croatia's capital), and 4 represented the involvement of the United States, Russia, the EU and the UN. The plan was the product of a process begun on 23 March 1994,[16] with Galbraith considering himself its principal author.[17] It was a well-developed legal document[18] intended as the basis for negotiations and, according to Ahrens, designed to commit Croatia to an internationally agreed settlement and prevent it from turning to a military resolution of the war[19] (while being generous to the Croatian Serbs). According to Ahrens, the plan was actually too generous to the Serbs;[18] in essence, it created the legal foundation for a permanent Serb state in Croatia.[20]

The heart of the plan was the Constitutional Agreement on Krajina (Part One). Part One defined Krajina as an autonomous region of Croatia, with borders based on the results of the 1991 Croatian census[19] (which identified eleven municipalities with an absolute Serb majority).[21] Those areas would enjoy a high level of autonomy, with most authority transferred from the central government in Zagreb to Krajina. The region would have its own president, cabinet, legislation, courts, police force, emblem, flag and currency, and the right to levy taxes and make international agreements.[19] Part One also provided for demilitarising the autonomous area. Part Two of the plan, the Agreements Concerning Slavonia, Southern Baranja, Western Sirmium and Other Areas, related to areas where the Croatian Serbs did not form the majority in 1991 (including eastern and western Slavonia) and contained transitional provisions. Part Three of the plan spelled out safeguards on human rights, fundamental freedoms, prosecution of war crimes, a human-rights court with international judges, and provisions allowing dual Croatian and Yugoslav citizenship for Croatian Serbs.[18] The plan envisaged that western Slavonia would be the first to be restored to Croatian control, followed by eastern Slavonia (where a transitional UN administration would be set up before the handover).[17]

Proposed changes

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The first draft of the Z-4 Plan was prepared in September 1994, and further developed and amended on several occasions during the following four months. Over this period, International Conference on the Former Yugoslavia (ICFY) co-chairs David Owen and Thorvald Stoltenberg requested amendments to the plan and opposed its presentation to Croatian or RSK authorities. The first set of changes requested was to include a provision that Croatia cede territory around the city of Županja (on the north bank of the Sava River) to the Federal Republic of Yugoslavia, allowing better communication between Belgrade and the Bosnian Serb territory around Banja Luka. The request, submitted on 8 September, was turned down by the plan authors.[22] That day, Owen requested that the plan allow Krajina to form a confederation with either Serbia or FR Yugoslavia. Owen and Stoltenberg sought to create a network of confederations between the former Yugoslav republics, but the authors of the Z-4 Plan deemed that impossible. German foreign minister Klaus Kinkel, on behalf of the German EU presidency, cautioned Owen that Krajina Serbs formed only 5 percent of Croatia's population and a confederation between Kosovo and Albania would be more natural. On 6 October Russia declared its opposition to the confederation, but Owen regained the country's support for the idea four days later (shortly before it was abandoned).[23]

The third group of requested amendments pertained to eastern Slavonia. Owen and Stoltenberg requested its status to be left unresolved, instead of gradually reverting to Croatian control over a five-year period and applying the postwar ethnic composition of the area as a formula for the ethnic mix of the local police and establishing a joint Croatian-Yugoslav company to extract crude oil in Đeletovci. The proposal was turned down, but it led to local autonomy for Serb villages in the area and reduced the transitional period to two years.[24] The fourth group of proposed amendments, tabled by Owen, included a proposal for continued Serb armed presence in Krajina and additional authority for Krajina concerning mineral resources and international treaties. After the proposals, the text of the plan became the subject of lengthy discussions between the contact group countries, the EU and the ICFY co-chairs. The co-chairs began drafting their version of the plan; Stoltenberg stalled the plan through Norwegian diplomat (and ICFY ambassador) Kai Eide,[25][26] creating a conflict between Eide and Galbraith.[27]

First news of the plan

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On 1 October, Galbraith informed Croatian President Franjo Tuđman of the plan without providing any details. Similarly, Ahrens and Eide informed RSK president Milan Martić.[19] Although early Z-4 Plan negotiations were planned without actually disclosing the plan to Croatia and the RSK,[25] elements of the plan were leaked to Belgrade and Zagreb newspapers in mid-October.[27] According to Florence Hartmann, in October representatives of Tuđman and those of Serbian president Slobodan Milošević met in Graz, Austria to discuss the proposed reintegration of the RSK into Croatia and their opposition to the Z-4 Plan.[28] Tuđman disliked the plan because it envisaged a Serb state in Croatia, while Milošević saw it as a dangerous precedent that could be applied to majority non-Serb or ethnically mixed regions of rump Yugoslavia, such as Kosovo, Vojvodina and the Sandžak.[29][30]

Galbraith, Eide and Kerestedjiants agreed to deliver the plan to Croatia and the RSK on 21 October, opposed by Owen and Stoltenberg. Owen also asked Vitaly Churkin to instruct his envoy to oppose the delivery. As instructed by Moscow, Kerestedjiants pulled out of the move and Galbraith accused Owen of sabotaging the Z-4 Plan.[31]

Final version

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The 53-page final version of the Z-4 Plan[32] was prepared on 18 January 1995. Entitled "Draft Agreement on the Krajina, Slavonia, Southern Baranja and Western Sirmium", it consisted of three documents and two provisional maps. The maps were considered provisional because of concerns that the inclusion of Benkovac in Krajina would be contested by Croatia; a portion of the municipality had been predominantly inhabited by Croats, and it was on the Adriatic coast. Another territorial issue was the municipality of Slunj; it was not included in Krajina, and the omission effectively cut Krajina in two. A possible solution to the problem was to split the municipality in two and award the areas east of Slunj to Krajina. In anticipation of this, planning began for a road bypassing Slunj. Despite the unresolved issues, delivery of the plan to Croatia and the RSK was scheduled for January.[33] On 12 January, shortly before the plan's final version was drafted, Tuđman announced in a letter to the UN that Croatia would not grant an extension of the UN peacekeeping mandate beyond 31 March and United Nations Protection Force (UNPROFOR) troops deployed to the RSK would have to leave.[34]

Presentation

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On 30 January the Z-4 Plan was presented to Tuđman by the French ambassador to Croatia, accompanied by Galbraith, Kerestedjiants, Ahrens and Italian ambassador Alfredo Matacotta (replacing Eide).[15] Tuđman did not hide his displeasure with the plan,[29] receiving the draft with the knowledge that Milošević's opposition to the plan (because of his concerns for Kosovo) would not allow it to be implemented.[35] Tuđman accepted the plan (which Croatia considered unacceptable) as a base for negotiations with the RSK,[32] hoping that they would dismiss it.[15]

The five diplomats then travelled to Knin to present the Z-4 Plan to the RSK leadership. There they met with Martić, RSK prime minister Borislav Mikelić and foreign minister Milan Babić. Martić refused to receive the draft before the UN Security Council issued a written statement extending the UNPROFOR mandate to protect the RSK. Kerestedjiants and Ahrens suggested that Martić should acknowledge receipt of the plan and then say that the RSK would not negotiate before the UNPROFOR issue was resolved, but he refused. The diplomats then attempted to meet Milošević in Belgrade about the matter, but Milošević refused to see them and the group returned to Zagreb the next day.[15] Ahrens described the events of 30 January as "a fiasco".[36]

Reactions

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Ahrens noted that Croatia and the RSK were satisfied with the outcome. Owen and Stoltenberg expressed their understanding of the RSK's and Milošević's rejection of the plan, provoking a sharp reaction from Galbraith.[36] The RSK parliament convened on 8 February with the Z-4 Plan as the sole item on the agenda. In their speeches there, Martić, Mikelić and Babić described the plan as provocative to the RSK and saw Milošević's support in refusing the plan as greatly encouraging.[37] A number of other influential Serbian politicians rejected the plan in addition to Milošević, including Borisav Jović—a close ally of Milošević, who considered the RSK strong enough militarily to resist Croatia—and Vojislav Šešelj, who considered the plan totally unacceptable. The opposition politicians in Serbia were split. Zoran Đinđić said that since the RSK refused the plan Serbia should not accept it either, while Vuk Drašković favoured the plan as an historic opportunity.[38] Drašković's views ultimately prevailed in the Serbian media, but not before late August.[39] The only official reaction from Croatia was from its chief negotiator, Hrvoje Šarinić. Šarinić said that Croatia endorsed the restoration of Croatian rule, the return of refugees and local self-government for Croatian Serbs, but dismissed plan solutions incompatible with the Constitution of Croatia.[32] In Croatia, the plan and its authors (especially Galbraith) were strongly criticised in what Ahrens described as a "vicious campaign".[36]

Attempts of reintroduction

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May and June 1995

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There were several more attempts to advocate the Z-4 Plan as the basis of a political settlement of the Croatian War of Independence. After Croatia captured western Slavonia from the RSK in Operation Flash in early May, Owen and Stoltenberg invited Croatian and RSK officials to Geneva in an effort to revive the plan. The initiative was endorsed by the UN Security Council and the G7, which was preparing its summit in Halifax at the time. The meeting was attended by Owen, Stoltenberg, Galbraith, Kerestedjiants, Eide and Ahrens as the international diplomats; the RSK was represented by Martić, Mikelić and Babić, and the Croatian delegation was led by Šarinić. Šarinić accepted the invitation, claiming that the venue was a Croatian concession because Croatian authorities considered the issue an internal matter which should normally be dealt with in Croatia. On the other hand, the RSK delegation insisted on Croatian withdrawal from the territory captured earlier that month before negotiations could proceed. Since no such withdrawal was requested by the UN Security Council, Croatia rejected the demand and the initiative collapsed.[40]

A second attempt to revive the plan arose from talks between Kinkel and French foreign minister Hervé de Charette on 28 June. They proposed establishing zones of separation to enforce a ceasefire, monitoring the RSK's external borders, specific guarantees for the safety of Croatian Serbs and implementing confidence-building measures by economic cooperation between Croatia and the RSK. The initiative, however, did not gain ground when the RSK refused to negotiate.[41]

August 1995

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Another effort involving the plan came about after Milošević asked the United States to stop an imminent Croatian attack against the RSK on 30 July. Although in his request he indicated that negotiations should be held based on the Z-4 Plan, he refused to meet Galbraith (who wanted Milošević to pressure the RSK into accepting it) on 2 August.[42] Instead, Galbraith met Babić in Belgrade in an effort to persuade him to accept the plan. He told Babić that the RSK could not expect international sympathy because of its involvement in the Siege of Bihać, and they would have to accept Croatian terms to avoid war. As an alternative, Galbraith advised Babić to accept negotiations based on the Z-4 Plan.[43] Babić complied, and Stoltenberg invited Croatian and RSK delegations to talks on 3 August.[41] Genthod, near Geneva,[44] was selected as the location to avoid media attention.[45] The RSK delegation was headed by Major General Mile Novaković of the Army of the Republic of Serb Krajina and the Croatian delegation was headed by Tuđman's advisor, Ivić Pašalić.[46]

At the meeting the RSK insisted on the withdrawal of the HV from western Slavonia and the gradual implementation of a ceasefire, followed by economic cooperation before a political settlement was discussed. The Croatian delegation did not intend to negotiate, but to prepare diplomatically for a military resolution of the war. Stoltenberg proposed a seven-point compromise, including negotiations based on the Z-4 Plan, beginning on 10 August.[46] The proposal was initially accepted by Babić, who then expressed reservations about the Z-4 Plan as a political settlement when he was asked to publicly declare support for the Stoltenberg proposal (so the Novaković delegation would follow his lead). Pašalić then asked Novaković to accept Croatia's seven demands,[47] including immediate replacement of the RSK with a Croatian civilian government.[46] Novaković refused Pašalić's proposal, indicating that he accepted the Stoltenberg proposal instead, and Pašalić declared that the RSK had declined a Croatian offer to negotiate.[47] Croatia did not consider Babić powerful enough to secure support for an initiative from Martić, and thus unable to commit the RSK to an agreement.[48] This view was supported by Babić himself, who told Galbraith during their 2 August meeting in Belgrade that Martić would only obey Milošević.[49] On 4 August Croatia launched Operation Storm against the RSK and, according to Galbraith, effectively terminated the Z-4 Plan and its associated political process.[16]

One final attempt, organised by Babić, was made to revive the Z-4 Plan on 16 August. This initiative called for negotiating each point of the plan and extending the autonomous areas to eastern Slavonia. However, Ahrens and Stoltenberg considered any talks between Croatia and the exiled, discredited leaders of the RSK impossible. When they consulted Šarinić about the initiative, he dismissed any possibility of negotiation.[50]

September 1995 and beyond

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Following Croatian military success against the RSK during Operation Storm in August, and in Bosnia and Herzegovina against the Republika Srpska during Operation Mistral 2 in September, US President Bill Clinton announced a new peace initiative for Bosnia and Herzegovina. This initiative, which aimed to restore eastern Slavonia to Croatia, was based on Croatian sovereignty and the Z-4 Plan. Gailbraith sought to reconcile the plan with new circumstances in the field;[51] an example was limited self-government for Croatian Serbs in eastern Slavonian municipalities where they comprised a majority of the 1991 population; after Croatia objected, the proposal was replaced with provisions from the Constitution of Croatia. By early October the process led to the Erdut Agreement, establishing a framework for restoring eastern Slavonia to Croatian rule.[52] When the agreement was first implemented in 1996, there were concerns in Croatia that the process might result in "covert" implementation of the Z-4 Plan in eastern Slavonia and political autonomy for the region.[53]

The Z-4 Plan was again resurrected in 1999 as a template for the Rambouillet Agreement, a proposed peace treaty negotiated between FR Yugoslavia and ethnic Albanians living in Kosovo.[30] In 2005, after the Kosovo War, Serbia and Montenegro attempted to resolve the Kosovo status process by tabling a peace plan offering broad autonomy for Kosovo. According to Drašković, then foreign minister of Serbia and Montenegro, the plan was a "mirror image of the Z-4 Plan".[54] That year an "RSK government-in-exile" was set up in Belgrade, demanding the revival of the Z-4 Plan in Croatia (a move condemned by Drašković and Serbian President Boris Tadić).[55] The same idea was put forward in 2010 by a Serb refugee organisation led by Savo Štrbac.[56]

Footnotes

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References

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Revisions and contributorsEdit on WikipediaRead on Wikipedia

Z-4 Plan

View on Grokipedia
from Grokipedia
The Z-4 Plan, also referred to as the Zagreb-4 Plan, was a peace proposal drafted in late 1994 and formally presented on 30 January 1995 by the International Contact Group—consisting of ambassadors from the United States, Russia, the United Kingdom, and France—to resolve the territorial dispute between Croatia and the self-proclaimed Republic of Serbian Krajina (RSK) amid the Croatian War of Independence. The initiative, spearheaded by U.S. diplomat Peter Galbraith and Russian counterpart Vitaly Churkin, aimed to reintegrate Serb-controlled areas into Croatia through a phased process granting the Krajina region extensive autonomy, including control over local administration, education, and cultural affairs, while affirming Croatian sovereignty, requiring demilitarization of the zone, ensuring refugee returns, and providing international guarantees for implementation. Key provisions delineated the autonomous territory to encompass Serb-majority areas in central and southern Croatia, such as around Knin and Glina, with Zagreb retaining authority over foreign policy, defense, and currency, alongside mechanisms for power-sharing and minority protections to prevent ethnic dominance. Despite representing a compromise short of RSK independence or full Croatian control, the plan faced immediate opposition: Croatian President Franjo Tuđman criticized it as overly concessional to Serb separatists, undermining central authority, while RSK leaders, influenced by Belgrade, initially rejected it for insufficient safeguards against Croatian dominance and demands for confederation with Serbia. Efforts to revive the Z-4 framework persisted into mid-1995, with RSK Prime Minister Milan Babić announcing conditional acceptance on 3 August, but Croatia proceeded with Operation Storm four days later, militarily recapturing the region and rendering the proposal moot, an action later justified by Zagreb as necessary due to the plan's failure but criticized internationally for subsequent human rights violations against Serb civilians. The Z-4 Plan thus stands as the final major international attempt at negotiated reintegration before forcible resolution, highlighting deep mistrust between the warring parties and the limitations of autonomy models in post-Yugoslav ethnic conflicts.

Historical Context

Outbreak and Course of the Croatian War of Independence

The Croatian War of Independence erupted amid the dissolution of Yugoslavia, triggered by rising ethnic tensions following Croatia's transition to multi-party democracy. In the April-May 1990 elections, the Croatian Democratic Union (HDZ) secured victory, with Franjo Tuđman elected president, prompting concerns among the Serb minority—comprising about 12% of the population—over potential discrimination and revival of World War II-era Ustaše policies. On August 17, 1990, Serb militants in Knin and surrounding areas initiated the "Log Revolution," erecting barricades with felled trees to block roads and assert autonomy, marking the first organized rebellion against Croatian sovereignty. This insurrection, supported by Serbia's leadership under Slobodan Milošević, expanded to declare the Serbian Autonomous District of Krajina on December 21, 1990, escalating from protests to armed standoffs. Clashes intensified in early 1991, with the first fatalities occurring during the Pakrac clash on March 1 and the on March 31, where (JNA) forces intervened to protect Serb rebels, killing one Croatian police officer. held an on May 19, 1991, with 93% approval among voters, followed by formal from on June 25, 1991, which the JNA—effectively controlled by Serb interests—opposed by seizing key installations. Initial battles, such as the May 2 Borovo Selo ambush, saw 12 Croatian policemen killed by Serb paramilitaries, highlighting the JNA's tacit support for Serb territorial grabs in regions like and . By July, JNA offensives enabled Serb forces to control approximately one-third of Croatian territory, including strategic areas along the Adriatic hinterland. The war's most brutal phase unfolded in eastern Croatia, exemplified by the 87-day siege of Vukovar from August 25 to November 18, 1991, where JNA and Serb units bombarded the city, resulting in nearly 1,500 Croatian military casualties and 1,131 civilian deaths, with the town left in ruins. Similar assaults targeted from October 1991, involving shelling that damaged sites, though Croatian defenses held the city. These operations, backed by Belgrade-supplied arms and troops, aimed to partition along ethnic lines, displacing tens of thousands of non-Serbs and entrenching de facto Serb control over self-proclaimed entities like the (RSK). Efforts to halt the fighting culminated in a UN-brokered ceasefire effective January 3, 1992, under the , which deployed the (UNPROFOR) to monitor three UN Protected Areas (UNPAs) encompassing Serb-held territories. This agreement froze frontlines but failed to resolve underlying disputes, leading to sporadic violations and Croatian counteroffensives, such as Operation Medak in September 1993, which expelled Serb forces from the Medak pocket at a cost of dozens of lives on both sides. The stalemate persisted into 1995, with Croatia launching in May to reclaim Western Slavonia, setting the stage for further diplomatic interventions amid ongoing JNA withdrawals and international pressure.

Creation of UN Protected Areas and Ceasefire Dynamics

The , erupting in March 1991, saw repeated attempts at amid escalating violence between Croatian forces and Serb paramilitaries backed by the (JNA). By late 1991, at least 14 ceasefire agreements had been negotiated but quickly violated, with major clashes in and underscoring the failure of prior truces. The 15th , agreed on January 2, 1992, as part of the Sarajevo Implementing Accord brokered by UN envoy , proved more enduring, facilitating the withdrawal of JNA heavy weapons and paving the way for UN-monitored zones. This accord implemented the Vance Plan, designating United Nations Protected Areas (UNPAs) in Serb-controlled territories to demilitarize them and prevent further hostilities. On February 21, 1992, UN Security Council Resolution 743 established the United Nations Protection Force (UNPROFOR), authorizing up to 14,000 troops to oversee the UNPAs, ensure JNA withdrawal by March 1992, and monitor local Serb police in maintaining order without heavy arms. The UNPAs encompassed four sectors—North (Eastern Slavonia around Vukovar), East (Western Slavonia around Okučani), West (Lika and Kordun around Slunj and Glina), and South (Dalmatian hinterland around Knin)—covering approximately 17% of Croatia's territory and housing over 300,000 Serbs. Ceasefire dynamics post-establishment were characterized by uneasy stability enforced by UNPROFOR's buffer presence, yet marred by persistent low-level violations, economic blockades imposed by on the UNPAs, and Serb authorities' refusal to disarm fully or recognize Croatian sovereignty. Incidents such as sporadic shelling across ceasefire lines and the 1993 "" blockade of highways demonstrated the fragility, with UNPROFOR often unable to enforce demilitarization strictly due to limited mandate and troop constraints. These dynamics entrenched a , isolating the self-proclaimed (RSK) economically and politically, while fostering Croatian resentment over delayed reintegration and Serb leverage through territorial control.

International Involvement and Diplomatic Framework

Role of the Zagreb-4 Contact Group

The Zagreb-4 Contact Group, also known as the mini-Contact Group, consisted of senior diplomats from the United States, European Union, Russia, and United Nations, who coordinated mediation efforts in Zagreb to resolve the Croatian conflict. Formed amid stalled International Conference on the Former Yugoslavia (ICFY) talks in late 1994, the group aimed to broker direct negotiations between the Croatian government and leaders of the self-declared Republic of Serbian Krajina (RSK) by proposing a comprehensive settlement framework. Its members included U.S. Ambassador Peter Galbraith, EU representative Geert-Hinrich Ahrens, Russian diplomat Leonid Kerestedjiants, and a UN envoy, reflecting a balance of Western, Eastern, and multilateral interests in containing the war's escalation. The group's primary role was to draft and iteratively refine the Z-4 Plan as a basis for ending hostilities, emphasizing Croatia's alongside transitional for Serb-majority areas in and . Operating from , they facilitated and preparatory meetings, culminating in the plan's presentation to both parties in under ICFY auspices by early 1995. This involved pressing for ceasefires—such as the fragile March 1995 truce—and addressing economic linkages, including joint exploitation of oil resources near the Serb-held areas, to build incentives for compliance. The mediators sought to sidestep RSK demands for outright independence by offering federal-like powers within , including veto rights on vital interests and international guarantees, while urging Belgrade's influence over Krajina Serbs to accept the terms. Despite these efforts, the group's mediation faltered as RSK President rejected the plan on February 8, 1995, insisting on revisions for secession, while Croatia viewed it as a maximal concession short of partition. The Zagreb-4's inability to enforce acceptance highlighted limitations in international leverage, particularly Russia's tacit support for Serb positions and U.S. reluctance to impose sanctions amid shifting Balkan priorities toward Bosnia. Ultimately, the group's work transitioned into post-conflict frameworks after Croatia's in August 1995 recaptured the areas, rendering the Z-4 obsolete but informing later reintegration models like the for eastern Slavonia.

Preceding Peace Initiatives

The , formally endorsed by 721 on November 27, 1991, and detailed in a UN ceasefire agreement signed on December 1, 1991, represented the first major international peace initiative to halt hostilities in . Negotiated by UN envoy , it called for an immediate , the withdrawal of (JNA) forces from , demilitarization of Serb-held territories designated as United Nations Protected Areas (UNPAs), and the deployment of the (UNPROFOR) to monitor compliance. The plan temporarily stabilized frontlines in regions like and Eastern by January 1992, but fragile implementation allowed sporadic violations, with fighting resuming in areas such as the Pocket in September 1993, underscoring its limitations in addressing underlying demands for Serb autonomy versus Croatian . Subsequent local-level initiatives sought to build on the Vance framework amid ongoing tensions. The Daruvar Agreement, signed secretly on February 18, , between Croatian government representatives and dissident Serb leaders in Western Slavonia (part of UNPA Sector West), aimed to normalize civilian life by facilitating utility restorations, returns, and transport reopenings, bypassing the hardline (RSK) leadership in . Similarly, the Christmas Truce Agreement of December 17, , mediated by UNPROFOR, established a temporary halt to hostilities in multiple sectors, including parts of , with provisions for joint patrols and economic normalization. These accords achieved limited successes, such as localized ceasefires and humanitarian access, but faced rejection or sabotage from RSK authorities aligned with , who prioritized partition over reintegration, highlighting divisions within Serb ranks and the inadequacy of subnational talks for comprehensive settlement. By 1994, diplomatic efforts shifted toward broader stabilization to enable political . A ceasefire brokered by Russian mediators in March 1994 reduced clashes across UNPA frontlines, creating space for economic between and RSK entities, including trade reopenings and infrastructure repairs as precursors to formal negotiations. These steps, coordinated informally through the emerging Zagreb-4 Contact Group (comprising ambassadors from the , , the , and ), built momentum from prior UN and European Community frameworks but stalled on core issues like and guarantees, as RSK insistence on confederation-like status clashed with Croatian demands for unitary sovereignty. The cumulative failures of these initiatives—marked by repeated Serb non-compliance and Croatian preparations—underscored the need for a structured political proposal, paving the way for the Z-4 Plan's drafting in late 1994.

Development of the Plan

Drafting and Iterative Revisions

The Z-4 Plan was drafted in the second half of 1994 by representatives of the Zagreb-4 Contact Group, which included ambassadors from the , , , and to Croatia, with a leading role played by U.S. Ambassador . The drafting process aimed to formulate a framework reconciling Croatia's insistence on with demands for Serb in regions of ethnic Serb majority, drawing on prior dynamics and UN-protected areas established since 1992. Iterative revisions occurred throughout late 1994 to address discrepancies among the mediating powers, including tensions between Western emphasis on Croatian and Russian support for Serb positions, as well as feedback from preliminary consultations with Croatian and self-proclaimed representatives. Suggested amendments to draft provisions, such as those on structures and arrangements, were advanced by , 1994, reflecting efforts to refine the plan's balance of elements with transitional reintegration mechanisms. These revisions positioned the Z-4 Plan as the third phase in a sequence of initiatives spanning approximately 10 months prior to its finalization. The completed draft, incorporating these adjustments, was presented to the Croatian government and Krajina Serb leadership on January 30, 1995, in , marking the culmination of the Contact Group's preparatory negotiations.

Key Figures and Influences

The Z-4 Plan was drafted by a mini-contact group comprising diplomats from the , , the , and representatives affiliated with the International Conference on the Former Yugoslavia. Central to its formulation was Peter W. Galbraith, the U.S. Ambassador to from 1993 to 1998, who actively engaged Croatian Serb leaders, including a meeting on January 30, 1995, to present and discuss the proposal as a basis for peace negotiations. Galbraith's role extended to advocating for provisions that balanced Croatian with limited Serb , reflecting U.S. interests in stabilizing the amid broader Yugoslav dissolution. Key collaborators included Leonid Kerestedjiants, the Russian Ambassador to Croatia, who contributed to the drafting process alongside Galbraith, and Geert-Hinrich Ahrens, a German diplomat serving as the EU's special envoy, who represented European perspectives emphasizing within a unified state framework. These figures operated under the Zagreb-4 framework, involving ambassadors from the U.S., , , and based in , which coordinated iterative revisions to address objections from both Croatian President and Serb leaders. The plan's influences drew from preceding diplomatic failures, such as the 1991 establishing UN Protected Areas, which had entrenched a partition without resolution, and ongoing UN peacekeeping shortcomings that failed to prevent sporadic violence. Broader geopolitical pressures, including NATO's emerging role and Russia's concerns over precedents for ethnic applicable to its own minorities, shaped the emphasis on demilitarization and over full independence for Serb-held territories. Serbian President Slobodan Milošević's reservations, viewing the model as a threat to parallel arrangements in Bosnia, indirectly influenced revisions but ultimately contributed to the plan's rejection by authorities.

Core Provisions

Territorial Integrity and Autonomy Framework

The Z-4 Plan's territorial framework explicitly affirmed the and of the Republic of , rejecting any form of or partition for Serb-majority areas and designating them as integral components of the Croatian state. The plan proposed unifying the Serb-controlled territories—primarily in , Western , and parts of Eastern —into a single autonomous region known as the "Region of Krajina," which would exercise subordinate to Croatian constitutional authority. This structure maintained Croatia's unified borders, with no internal checkpoints or customs barriers between the autonomous region and the rest of the country, ensuring free movement of people and goods. Autonomy provisions granted the region extensive powers over local affairs to safeguard Serb ethnic interests, including control over , , , , public information, , public services, , , trades, taxation, and local expenditures. The region would also manage its own police forces for internal security, subject to Croatian oversight on national standards, while the Croatian government retained exclusive authority over defense, , , , communications, and . Demilitarization was a core element: existing Serb militias would disband, with Croatian armed forces assuming responsibility for external defense and , potentially with transitional UN monitoring along the Bosnia-Herzegovina frontier. To balance reintegration, the plan outlined phased implementation, with certain peripheral Serb-held areas reverting to direct Croatian administration immediately or within two years, while the core autonomous region received enhanced self-rule protections, including veto rights over legislation affecting vital Serb interests and in national institutions. This framework drew on international precedents for minority , aiming to prevent recurrence through constitutional safeguards rather than territorial concessions.

Governance, Rights, and Security Measures

The Z-4 Plan proposed governance structures granting substantial autonomy to regions where Serbs constituted a pre-war majority, positioning these areas as self-governing entities within Croatia's framework. Local legislative authority would reside in a regional assembly empowered to enact laws on , , and , while an executive body—potentially led by a regional president—would oversee administration, including taxation powers. This setup subordinated regional decisions to Croatian in , defense, and , with shared usage and proportional Serb representation in national institutions such as the to safeguard rights on vital interests. Human rights provisions emphasized protections for ethnic minorities, including guarantees of non-discrimination, , and cultural preservation, such as the right to use Serb symbols like a regional and to maintain a distinct system in the Serb language. The plan included mechanisms for prosecuting war crimes through a specialized incorporating international judges and established an office with international participation to monitor compliance with fundamental freedoms. These elements aimed to address Serb concerns over marginalization while ensuring Croatian authority prevented secessionist tendencies. Security measures required demilitarization of the autonomous regions, barring the maintenance of any Serb forces and restricting armament to a regional police force responsible for internal order, potentially organized on ethnic lines during transition. The Croatian armed forces would control external borders and national defense, with Serbs required to recognize Croatia's unconditionally. envisioned a transitional international presence, possibly under UN auspices, to oversee , confidence-building, and phased integration, mitigating risks of renewed conflict.

Economic and Return Provisions

The Z-4 Plan established that the Serb-held areas would integrate into Croatia's national economy as a single economic space, eliminating internal tariffs and barriers to the free movement of goods, services, capital, and labor across the country. This framework preserved Croatia's unified and with international partners, while permitting the autonomous regions limited authority over local and to address specific community needs. Complementing these measures, preliminary economic agreements under the Zagreb-4 framework had already facilitated reconnection, including a , 1994, accord between Croatian authorities and Republika Srpska Krajina representatives to reopen a segment of the Zagreb-Belgrade highway and an oil pipeline traversing Serb-controlled western , signaling intent for broader economic normalization. The plan's return provisions affirmed the universal right of refugees and internally displaced persons—encompassing both the roughly 200,000 Croats expelled from Serb-held territories and any Serbs displaced from Croatian-controlled areas—to repatriate to their original residences without hindrance. It mandated restitution of confiscated properties or fair compensation where restoration proved infeasible, alongside non-discrimination guarantees in housing, employment, and public services to support sustainable reintegration.

Presentation and Reception

Official Launch and Public Disclosure

The Z-4 Plan, formally titled the "Draft Agreement on the , , Southern Baranja and Western Srem," was officially presented to the parties on January 30, 1995. The document, comprising 53 pages, had been finalized earlier that month following iterative revisions by the Zagreb-4 Contact Group, consisting of representatives from the , , the , and . The presentation to Croatian President occurred in , delivered by the group's ambassadors, including U.S. Ambassador and counterparts from the other nations. A parallel presentation was extended to the leadership of the self-proclaimed Republika Srpska in , though initial reception there was marked by reluctance to engage formally. Public disclosure of the plan's core elements—such as limited Serb in designated regions while affirming Croatia's —occurred concurrently through international press coverage. Reports detailed the proposal's framework for self-government in Serb-majority areas, including provisions for dual citizenship, , and phased demilitarization, positioning it as the culmination of months of diplomatic drafting aimed at resolving the . This launch represented the third major iteration in a series of initiatives, building on prior efforts like the 1994 framework but escalating to a comprehensive settlement offer. The timing aligned with heightened international pressure for resolution amid ongoing stalemates in UN-monitored ceasefires.

Croatian Government Acceptance

The Z-4 Plan, drafted by representatives from the , , , and the , was formally presented to Croatian President on January 30, 1995, in . The Croatian government, facing mounting international pressure to pursue a negotiated settlement amid ongoing hostilities with the self-proclaimed Republika Srpska Krajina (RSK), agreed to accept the plan as a framework for further talks rather than a final agreement. This stance was articulated publicly by Tuđman in early February 1995, signaling Zagreb's willingness to engage despite internal dissatisfaction with provisions granting substantial autonomy, including joint control over borders, a separate Serb-region , and veto rights on minority-related legislation. Acceptance served strategic purposes for Croatia, including preserving support from Western powers like the , which had conditioned and diplomatic on demonstrated efforts. Tuđman viewed the plan as imperfect but preferable to isolation, particularly after recent Croatian gains in western had strengthened bargaining position; however, he insisted on Croatia's non-negotiable and rejected any implication of partition. Diplomatic records indicate that while Croatia endorsed the Z-4 as a starting point, it sought revisions to limit Serb and ensure authority over , defense, and . Subsequent efforts to implement the plan faltered when RSK leaders refused it outright, but 's conditional endorsement allowed it to maintain a facade of compliance with international mediators through mid-1995. Analyses from declassified diplomatic cables highlight that Tuđman's agreement was pragmatic, aimed at averting sanctions or arms embargoes, though domestic critics within argued it conceded too much to Serb separatists backed by . No full ratification occurred, as negotiations collapsed, paving the way for military resolution.

Republika Srpska Krajina Rejection

The Z-4 Plan, formally presented to the leadership of the Republika Srpska Krajina (RSK) in January 1995, was rejected by RSK President on 30 January 1995. The plan proposed extensive for Serb-majority areas based on the 1991 census, including a separate , police force, , fiscal policy, and institutional links with , while maintaining 's overall sovereignty and prohibiting . Martić's rejection stemmed from a fundamental opposition to reintegration into , prioritizing Serb goals of independence or union with over the offered framework, amid deep distrust of Croatian intentions exemplified by Zagreb's initial refusal to extend the UNPROFOR mandate. Internal divisions within RSK leadership further complicated acceptance, with Borislav Mikelić advocating support for the plan's provisions, while hardliners like Martić and former leader viewed it as insufficient to safeguard Serb interests against perceived Croatian aggression. Serbian President exerted significant influence, directing Martić to reject the Z-4 Plan a priori, as corroborated by witness testimonies including those of Rade Rašeta on 2 May 2006 and Mile Dakić on 25 October 2006. This stance aligned with Belgrade's broader strategic priorities, which favored maintaining leverage in ongoing conflicts rather than conceding to arrangements that could undermine Serb positions elsewhere, such as in Bosnia. Efforts to revive negotiations in mid-1995 faltered amid escalating tensions, including Croatia's in May 1995. Although Babić expressed acceptance of the plan "in substance" on 2 August 1995, the RSK leadership as a whole did not endorse it, citing unresolved demands for territorial guarantees and security assurances. The rejection precluded a political resolution, contributing directly to the military dynamics that culminated in on 4 August 1995.

Negotiation Efforts and Breakdown

Early 1995 Diplomatic Push

In January 1995, the Contact Group—consisting of representatives from the , , the , and the —launched a coordinated diplomatic initiative to promote the Z-4 Plan as a framework for resolving the Croatian conflict. The plan, which had been drafted over preceding months, was formally presented on January 30 to Croatian President and leaders of the self-proclaimed Republika Srpska Krajina (RSK). This effort aimed to avert renewed hostilities amid the impending expiration of the (UNPROFOR) mandate on March 31, which Croatia refused to extend, potentially leaving Serb-held territories vulnerable. Diplomats positioned the proposal as offering the maximum feasible autonomy to Serbs in majority areas—nearly one-third of Croatia's territory—while requiring recognition of Croatian sovereignty, including cession of non-majority zones and Croatian control over borders. US Ambassador played a central role, traveling to on January 30 to brief RSK President and other Serb leaders on the plan's details, which included provisions such as a separate flag, parliament, police force, and educational system for Serb areas. Martić rejected the document summarily, refusing to touch it, signaling immediate RSK intransigence tied to consultations with Serbian President . The next day, January 31, both RSK officials and Milošević declined meetings with Z-4 mediators, insisting on extended UNPROFOR presence beyond Croatia's July 1 deadline for full territorial reintegration. Tuđman received the plan with measured engagement, privately expressing dissatisfaction with its autonomy elements but avoiding outright dismissal to preserve alignment with the and avoid isolation. Western diplomats described the push as a critical, last-ditch opportunity, emphasizing practical implementation rules over abstract political language to bridge divides. Despite these overtures, the initial phase yielded no breakthroughs, as Serb demands for prolonged international protection clashed with Croatian insistence on , foreshadowing stalled negotiations.

Mid-1995 Reintroduction Attempts

In the wake of Croatia's , which recaptured the Western Slavonia region on May 1–3, 1995, the Contact Group—comprising diplomats from the , , the , and the —intensified diplomatic initiatives to revive the Z-4 Plan as a foundation for resolving the conflict. These efforts, conducted primarily through negotiations between Croatian officials and Republika Srpska Krajina (RSK) representatives, sought to build on the plan's provisions for Serb autonomy within Croatian borders amid heightened military pressures on Serb-held areas. During May and June 1995, multiple sessions emphasized the Z-4 framework's potential for transitional administration, demilitarization, and protections, with U.S. and Russian mediators urging compromise to avert further escalation. Croatian President expressed readiness to negotiate on the plan's basis, viewing it as aligned with Zagreb's insistence on , while UN co-chair facilitated discussions to address Serb security concerns. However, RSK President and other leaders consistently rebuffed the proposals, refusing even to handle copies of the document and demanding guarantees of effective veto powers or separation not contained in the plan. The stalled talks reflected deeper RSK skepticism toward international guarantees, exacerbated by fears of Croatian dominance and perceived biases in Contact Group mediation favoring reintegration over . By midsummer, these reintroduction attempts had yielded no substantive progress, contributing to a diplomatic that persisted until military developments overtook negotiations.

Underlying Reasons for Serb Intransigence

The (RSK) leadership's rejection of the Z-4 Plan in July 1995 was rooted in a fundamental preference for full separation from over any form of reintegration, even with substantial provisions. RSK President explicitly refused to receive the proposal document when presented by diplomats, signaling an unwillingness to engage with terms that subordinated Serb-held territories to Croatian . This stance reflected broader aspirations among RSK hardliners for either outright or incorporation into , rather than the plan's framework of a demilitarized autonomous region within Croatia's borders, complete with its own assembly, police, and fiscal policies but subject to Zagreb's ultimate authority. Territorial concerns exacerbated this intransigence, as the Z-4 Plan delimited the autonomous "" to areas with Serb majorities according to the 1991 census, excluding regions under RSK control that had mixed demographics or had been seized during the 1991-1992 fighting, such as parts of the and . Retaining control over these expanded holdings was seen as essential to leverage future negotiations or military defense, and conceding them would have undermined the RSK's statehood claims established since 1991. Internal divisions within the RSK further hardened positions, with moderates like facing dominance by militaristic factions who prioritized confrontation, anticipating either sustained UN protection under UNPROFOR or external support from that failed to materialize. Distrust of Croatian intentions, fueled by Zagreb's prior military operations like in May 1995—which recaptured Western Slavonia despite international mediation efforts—reinforced Serb leaders' conviction that autonomy guarantees would prove illusory under a perceived as intent on reasserting full control. Analyses indicate that RSK elites miscalculated the shifting international dynamics, including waning support from Slobodan Milošević, who viewed the plan as viable but whose influence over had eroded by mid-1995 amid his focus on Bosnia. This combination of ideological commitment to separation, territorial maximalism, and overconfidence in the status quo ultimately precluded acceptance, despite the plan's concessions exceeding prior offers like the 1991 ZNG plan.

Immediate Aftermath

The rejection of the Z-4 Plan by Republika Srpska (RSK) leadership on March 2, 1995, extinguished the principal international framework for a negotiated resolution to the Croatian conflict, thereby clearing the path for Croatia's military reunification efforts. The plan had offered Serb-held areas extensive autonomy, including joint control over , defense, and border issues, while affirming Croatia's —a compromise Croatia had provisionally endorsed in February 1995. RSK authorities, influenced by ties to , dismissed it as insufficient, demanding full separation or union with , which underscored their prioritization of irredentist goals over pragmatic accommodation. This diplomatic impasse, following prior failed initiatives like the 1994 Zagreb Agreement, shifted momentum toward force. , having modernized its armed forces with U.S. training and equipment since 1992, had been preparing offensive operations independently of Z-4 talks, viewing military action as a fallback to diplomacy. The plan's collapse neutralized objections from mediators like the U.S., , , and UN—who had pressed for its implementation—reducing anticipated backlash against Croatian advances. In May 1995, tested this leeway with , swiftly retaking Western (a region partially addressed but not core to Z-4's autonomy zones) with minimal international condemnation, capturing 600-900 Serb fighters and prompting 15,000 civilian displacements. By early August 1995, the Z-4's definitive failure—coupled with RSK non-compliance on cease-fires and demilitarization—provided Croatia's justification for Operation Storm, launched on August 4 against the larger Krajina enclave. The offensive overwhelmed RSK defenses in Knin and surrounding areas within 84 hours, involving 130,000-150,000 Croatian troops and allied Bosniak forces, resulting in the flight of approximately 150,000-200,000 Serbs and the reintegration of 10,400 square kilometers of territory. U.S. Ambassador Peter Galbraith, co-drafter of Z-4, observed that Storm effectively ended the proposal's viability, reflecting a consensus among Western powers that Serb rejection had forfeited diplomatic protections. While Croatian planning for Storm predated the rejection (initiating in late 1994), the Z-4 breakdown removed procedural hurdles, enabling execution without the paralysis of active negotiations.

Casualties and Population Movements

Operation Storm, launched by Croatian forces on August 4, 1995, shortly after the Republika Srpska Krajina (RSK) leadership's rejection of the Z-4 Plan, resulted in the rapid recapture of the self-proclaimed RSK territory. Croatian military casualties were relatively low, with 174 soldiers killed and around 1,000 wounded, reflecting the swift collapse of RSK defenses. Army of the Republic of Serbian Krajina (ARSK) losses were significantly higher, estimated at several hundred combatants killed, though exact figures remain contested due to the disorganized Serb retreat. Civilian casualties during and immediately following the operation were predominantly among the Serb population and highly disputed across sources. Croatian authorities reported 116 Serb civilian deaths as of August 30, 1995, but documented at least 150 summary executions of Serb civilians in the aftermath, with U.N. investigators and local NGOs estimating up to 700 such killings. The Croatian Helsinki cited at least 677 total persons killed during the operation itself. A 2025 study by the Croatian NGO , covering the period from July 25, 1995, to January 14, 2001, identified 2,353 victims associated with , including 1,170 civilians (1,055 Serbs) killed or missing, primarily through (1,073 cases) or disappearance (383 cases); this figure encompasses both immediate combat and extended reprisals, with verification based on cross-referenced documentation. Serbian sources often claim over 1,000 civilian deaths, while Croatian estimates remain lower, highlighting ongoing debates over accountability and forensic evidence from sites like mass graves. The operation triggered one of the largest refugee crises in the , with approximately 200,000 Serbs fleeing the region during the August 4–7 offensive, primarily to (including ) and Serb-held areas in Bosnia such as . This exodus, facilitated by ARSK orders and fears of reprisals amid shelling and advancing forces, left Serb-majority areas depopulated overnight; UNHCR data indicated only about 3,000 returns by April 1996, with systemic barriers including property confiscations and discriminatory policies impeding repatriation for years. The displacement effectively ended organized Serb resistance in but contributed to long-term demographic shifts and unresolved claims of , as later examined by the International Criminal Tribunal for the former (ICTY).

Long-Term Impact and Analysis

Influence on Dayton Accords and Regional Stability

The failure of the Z-4 Plan, rejected by Serb leader in January 1995 and undermined by Croatian President Franjo Tuđman's preference for military resolution, directly precipitated from August 4 to 8, 1995, which reintegrated Serb-held territories into by force. This offensive, supported by U.S.-provided military training through the private firm (MPRI) and tacit Washington approval signaled on July 25, 1995, shifted the regional balance of power decisively against Serb forces, demonstrating the limits of proposals without enforcement mechanisms. The resulting displacement of approximately 150,000 to 180,000 Serbs weakened the broader Serb position in the , pressuring Serbian President to engage more constructively in parallel Bosnian negotiations. This momentum contributed to the Dayton Agreement, initialed on November 21, 1995, which partitioned Bosnia and Herzegovina into a 51% Bosniak-Croat federation and 49% Republika Srpska entity while preserving its sovereignty. The Croatian military success, combined with NATO's Operation Deliberate Force air campaign against Bosnian Serb positions starting August 30, 1995, compelled Milošević to represent Bosnian Serbs at Dayton after their leadership's intransigence, as U.S. negotiator Richard Holbrooke leveraged the post-Storm realities to extract concessions. The Erdut Agreement of November 12, 1995, for the peaceful reintegration of Eastern Slavonia—Baranja and Western Srem under UNTAES administration—served as a precondition for Tuđman's attendance at Dayton, illustrating how Z-4's collapse redirected diplomatic efforts toward transitional models that prioritized stability over maximalist autonomy. In terms of regional stability, the Z-4 Plan's breakdown and the ensuing military resolution ended Croatia's four-year war of independence on August 8, 1995, allowing to consolidate control and redirect resources toward supporting Bosniak forces, which bolstered the Croat-Bosniak framework from March 1, 1994. This facilitated the cessation of hostilities across former Yugoslav fronts by late 1995, with Eastern Slavonia's elections in April 1997 and full Croatian assumption of authority by January 15, 1998, marking a rare peaceful ethnic reintegration where most Serbs remained. However, the plan's failure entrenched ethnic homogenization in through mass exodus and reported abuses, complicating long-term minority returns and fostering resentment that persisted in Serb-Croatian relations, though it arguably prevented prolonged partition akin to Bosnia's Dayton-imposed stasis. Overall, by resolving Croatia's conflict militarily after diplomacy faltered, the Z-4 episode underscored the causal primacy of force over negotiation in compelling Balkan actors toward settlement, contributing to a fragile but operative peace that halted immediate escalations.

Achievements: Potential for Peaceful Resolution

The Z-4 Plan proposed substantial territorial autonomy for Serbs in pre-war majority areas of , encompassing self-governance through a dedicated , executive authority, police force, education system, , and even a distinct , while requiring recognition of Croatia's international borders and Croatian presence along them. This structure aimed to reintegrate Serb-held territories politically rather than through force, building on prior economic cooperation agreements between and signed in December 1994 that had eased some tensions. Croatian President , despite initial reservations, accepted the plan on January 30, 1995, as a foundation for further talks, demonstrating Zagreb's preparedness to concede significant powers to secure a non-military resolution amid expiring UN mandates. International mediators, including U.S., U.K., Russian, and German representatives, viewed it as a comprehensive framework to avert renewed hostilities, positioning it as a "last chance" before potential Croatian offensives. Had Serb leaders endorsed it, the plan held potential to prevent the escalatory violence of , including the displacement of approximately 150,000–250,000 Serbs and hundreds of military casualties, by enabling gradual demilitarization and joint policing under international oversight. Its emphasis on confederation-like arrangements influenced later models, such as the November 1995 for Eastern Slavonia, Baranja, and Western Srem, which successfully reintegrated remaining Serb-controlled areas peacefully via UN administration starting in January 1996. Thus, the Z-4 initiative underscored the viability of autonomy-based diplomacy in resolving ethnic territorial disputes without partition or ethnic homogenization.

Criticisms: Flaws in Design and Implementation

The Z-4 Plan's design was criticized for proposing an excessively decentralized form of autonomy that effectively created a proto-state within Croatia, granting Serb-majority regions control over their own parliament, police force, fiscal policy, currency, and even international symbols like a flag and anthem, while maintaining nominal Croatian sovereignty. Croatian President Franjo Tuđman and Prime Minister Nikica Valentić opposed these provisions, arguing they would lead to Croatia's de facto dissolution by institutionalizing ethnic separation and undermining central authority, as the plan relied on the 1991 census to define Serb-majority areas without mechanisms to prevent future territorial fragmentation. From the Serb perspective, the plan's autonomy fell short of secessionist goals and lacked credible enforcement guarantees, exacerbating distrust rooted in prior unfulfilled agreements like the 1991 Z-4 framework and perceived violations of UN-monitored ceasefires. (RSK) leaders, including , rejected it outright, citing the impending expiration of the UNPROFOR mandate in March 1995 as evidence that international protection would evaporate, leaving Serbs vulnerable to Croatian military reconquest without binding international troops or sanctions to uphold the accord. Implementation flaws stemmed from the plan's dependence on voluntary compliance amid profound mutual enmity and conflicting great-power interests, with U.S. and mediators pushing for rapid reintegration while sympathized with Serb concerns, resulting in inconsistent diplomatic pressure. Internal divisions within the RSK leadership—such as Borislav Mikelić's tentative support versus Martić's and Milan Babić's opposition—paralyzed decision-making, while Belgrade's rejection under , viewing it as a precedent for autonomy, further eroded its viability. The absence of phased or interim international administration beyond a vague five-year UN presence in Eastern doomed the plan to collapse, paving the way for military resolution in August 1995.

Diverse Viewpoints: Serb, Croatian, and International Perspectives

Serb perspectives on the Z-4 Plan emphasized deep of Croatian intentions, viewing the proposed as illusory and vulnerable to future revocation once Serb forces demilitarized and integrated into state structures. Krajina Serb leaders, including President , rejected the plan upon its presentation on January 30, 1995, arguing it failed to secure permanent for areas beyond strict ethnic majorities that they controlled, and required concessions like lifting the economic only after compliance. Influence from played a role, as reportedly opposed it fearing a for territorial losses in Bosnia, prioritizing strategic leverage over Krajina's local interests. Some Krajina figures, such as Prime Minister , later claimed conditional acceptance in talks on August 2–3, 1995, citing assurances from U.S. Ambassador against Croatian aggression, though this was not ratified by the RSK presidency and is contested in accounts sympathetic to Serb positions. Croatian viewpoints framed the Z-4 Plan as excessively favorable to Serbs, effectively partitioning the country by granting a self-governing unit with its own constitution, flag, anthem, presidency, assembly, supreme court, and police force—powers exceeding those of Croatia's counties and including veto rights over laws affecting Serb interests. President Franjo Tuđman and government officials criticized these elements as creating a "state within a state," incompatible with Croatia's sovereignty after four years of Serb rebellion and occupation of 30% of its territory since 1991. While Zagreb initially engaged in negotiations and accepted the plan as a basis for talks in principle, Tuđman prioritized military reintegration, viewing sustained autonomy as rewarding aggression and hindering refugee returns or economic normalization. International perspectives, shaped by the Contact Group (ambassadors from the U.S., , , and U.K.), positioned the Z-4 Plan as a pragmatic compromise drafted by U.S. diplomat and German mediator Evelyn Kolker, balancing Croatia's with extensive Serb rights including joint over borders, foreign policy input, and demilitarized zones. Mediators attributed primary failure to Serb intransigence, interpreting the Knin leadership's refusal to even handle the document as evidence of irredentist goals tied to ambitions, which undermined peace efforts and lent tacit support to Croatia's subsequent on August 4, 1995. Later analyses, including from U.N. documents, acknowledged flaws like unenforceable guarantees amid mutual distrust but upheld the plan's generosity toward Serbs compared to prior proposals; however, sources critical of Western policy highlight U.S. acquiescence to Croatian military action despite private awareness of ethnic displacement risks, reflecting geopolitical prioritization of ending the conflict over strict mediation.

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