The Unification Decree was a political measure adopted by Francisco Franco in his capacity of Head of State of Nationalist Spain on April 19, 1937. The decree merged two existing political groupings, the Falangists and the Carlists, into a new party - the Falange Española Tradicionalista y de las Juntas de Ofensiva Nacional Sindicalista (FET y de las JONS). As all other parties were declared dissolved at the same time, the FET became the only legal party in Nationalist Spain. It was defined in the decree as a link between state and society and was intended to form the basis for an eventual totalitarian regime modeled after Fascist Italy and Nazi Germany. The head of state – Franco himself – was proclaimed party leader, to be assisted by the Junta Política and Consejo Nacional. A set of decrees which followed shortly after appointed members to the new executive.

The merger was imposed upon the Falange Española de las JONS and the Carlist Traditionalist Communion. Leaders of both parties – Manuel Hedilla of the Falange and Manuel Fal Conde of the Carlists – were outmaneuvered by Franco, who divided, deceived, and misled them and finally left them no option but to comply with unification on his own terms, and they along with other political opponents were subsequently marginalized. The Unification Decree ensured Franco's total political dominance and secured at least a formal political unity within the Nationalist zone, albeit not one of genuine affection. It in reality represented the absorption of Carlist offshoots into a subsequently domesticated and subordinated Falange. Most scholars consider unification to have been a stepping stone towards a semi-fascist state. This augmented Falange served as Spain's sole legal party for the next 38 years, becoming one of the instrumental pillars of Franco's regime.

The military conspirators of 1936 did not produce any clear vision of a political regime which would follow the coup; in the short run, some administrative powers were to stay with provincial civil committees, composed of most representative or most committed individuals. The key right-wing factions in Spain were rather loosely involved in the plot, and almost none of them concluded a political agreement with the generals. The only party which did close a deal, the Carlists, secured an ambiguous agreement with the head of the conspiracy, General Emilio Mola; it specified terms of access to the coup rather than a future political regime. Initial statements issued by various generals during the first days of the following rebellion remained politically vague; on territories controlled by the rebels local commanders appointed mayors or auxiliary civilian bodies composed mostly of locally recognized right-wing personalities, typically those associated with CEDA, Alfonsism, Carlism, or the defunct Spanish Patriotic Union. The top executive body of the rebel government, the Junta de Defensa Nacional, was set up on July 23 as an instrument of administration and intendancy rather than politics. On July 30 the Junta declared martial law, which theoretically prevented any political activity. On September 13 the Junta issued a decree which dissolved all Popular Front parties and those opposed to "the patriotic movement". Soon afterwards it condemned "political partisanship" though not "specific ideologies", stating that the future government would introduce "the only politics and the only unionization possible" and prohibited all political or trade union activities.

This ban on political activity was not rigorously enforced on rightist organizations, but each of their fates differed significantly. The largest grouping, CEDA, which held 88 seats in the Cortes, had been gradually disintegrating since the February elections; its structures had partially collapsed, having been abandoned by militants disappointed with the movement's legalist strategy. In addition, its leader José María Gil-Robles y Quiñones declared the suspension of all CEDA political activity. Though some of CEDA heavyweights remained politically active, Juventudes de Acción Popular (JAP), CEDA's youth wing and formerly its most dynamic organ, reorganized in September 1936 as a paramilitary force with few thousand members. Renovación Española (13 mandates) and Partido Agrario (11 mandates) were also in decay, with the Alfonsists of RE in particular being preoccupied with engineering schemes related to Infante Juan, Count of Barcelona. The two groups on the right which did experience growth, and at a dramatic rate, were the Carlist Comunión Tradicionalista and the Falange Española de las JONS. Comunión Tradicionalista (10 mandates) openly operated its national and provincial war councils, its key asset being volunteer militia units, the Requetés, which in the first months of the war claimed 20,000 men. The Falange, which in February obtained only 0.4% of the votes and lost its previously held one seat in the Cortes, experienced enormous growth in subsequent months and would come to be the most dynamic of party on the right. Its party structures functioned without restriction; its Primera Línea militias recruited 35,000 volunteers in a short period.

In early October 1936 supreme power in the rebel zone was assumed by Francisco Franco, who set up an executive administration named the Junta Técnica del Estado. The civilians appointed to head specific sections of this quasi-government "resembled the traditional Right" and were recruited from Alfonsist, Carlist, and other generic conservative ranks, with no specific party background prevailing. The regime permitted limited political proselytizing but kept politicians in check; CEDA head Gil-Robles was forced to remain in Portugal, Infante Juan, championed by the Alfonsists, was asked to leave Spain, Prince Xavier of Bourbon-Parma, the Carlist pretender to the throne, was permitted only a brief stay in Spain, and the leader of the Comunión Tradicionalista, Fal Conde, was exiled with inflated charges advanced. Military censorship prevented dissemination of pieces deemed excessively related to party propaganda and encouraged these kept within limits of general adhesion to the regime, e.g. Gil-Robles' order that JAP must fully follow military command or RE head Antonio Goicoechea's call for a "patriotic front". Franco himself kept meeting with right-wing politicians, usually ignoring the intransigent ones and speaking only to these deemed tractable. No political plans were discussed. In general, his guests were expected to mobilize civilian support for the regime with no political commitment offered in return, except that in an unspecified future "the people" would be free to decide the future regime of Spain.

Few months into the civil war it was already evident that the balance of power among right-wing parties underwent a major shake-up. The decomposed CEDA, Renovación and Agrarians were dwarfed by Comunión Tradicionalista and Falange Española, two groupings responsible for some 80% of volunteers in ranks of the Nationalist party militias. It was their efficiency as recruitment structures which mattered to Franco and the military. Initially volunteers constituted 38% of all troops available to the Nationalists on the peninsula; as conscription was getting implemented by November this figure went down to 25%. Both groupings were increasingly viewing themselves as future masters of new Spain. The Carlists considered themselves exclusive political partners of the military as agreed back in July 1936; they saw the Nationalist faction as basically a Carlist-military alliance. The Falangists saw the Nationalist effort very much in terms of a syndicalist revolution, with Falange the only genuine live political force amidst remnants of old, pathetically antiquated other parties. Both CT and FE considered the army – even though viewed with some suspicion as respectively liberal or reactionary – a necessary tool to gain control of all Spain, but they expected the army to be politically passive and each claimed exclusive right to define political content of the future state.

The most dynamic political power was Falange; a 1933-born third-rate party known mostly for street violence and as a point of reference for Spanish Fascism, in the atmosphere of rapid radicalization of 1936 it attracted tens and soon hundreds of thousands of mostly young people. With its leader José Antonio Primo de Rivera and many other top activists trapped in the Republican zone, in September 1936 Falange formed a provisional Junta de Mando composed of largely inexperienced young leaders and headed by Manuel Hedilla; the party kept developing its structures, building youth, female, children, propaganda, paramilitary, student, syndicate, sanitary and other sections. By late 1936 Falange supplied some 55% of all volunteers and clearly outpaced the Carlists; apart from former CEDA or Renovación militants, also some right-wing republicans started to join Falange in order to counterbalance the monarchist Carlists. Franco kept meeting Hedilla, listened to his advice and even made some effort to flatter him, yet he usually denied Hedilla's requests. The Falangist executive, itself divided mostly along personalist lines between Hedillistas and so-called “legitimists”, were getting increasingly frustrated about military domination; in early 1937 they empowered Hedilla to demand total political hegemony with military control reduced to the army and the navy. Moreover, in January the Junta reached to the German NSDAP and the Italian PNF seeking a political understanding behind the back of the military; they vaguely suggested that “Franco is [only] for today”.

In the early 20th century Carlism was a second-rate force; like Falange it benefited from radicalization of the mid-1930s, though unlike Falange it enjoyed major appeal only in some regions of Spain. The Carlist pretender, the Austria-based Don Alfonso Carlos, perished in late September 1936 and was succeeded by a regent, France-based Don Javier. The latter met Franco twice in 1936 and both leaders remained highly skeptical about each other; Franco preferred to speak to the experienced Navarrese leader, conde Rodezno. Like Falange, the Carlists tried to make their best of the autonomy allowed by the military administration; in October 1936 their propaganda paid more attention to Don Javier assuming the regency than to Franco assuming the state jefatura, and in late 1936 headlines of Carlist press exalted the exiled leader Fal Conde as caudillo, reserving for Franco only small-font notes at the bottom of the page. In December the Carlists launched their own syndicalist scheme. In early 1937 Carlism started to demonstrate agglutinatory appeal; some CEDA politicians discussed merger, a small Partido Nacionalista Español merged indeed, an independent syndicalist organization CESE joined the Carlist Obra Nacional Corporative scheme and in some regions Acción Popular and Renovación sections fused with the Carlists. In Navarre the Carlists ran sort of an own state structure.