Swedish neutrality

Sweden had a policy of neutrality in armed conflicts from the early 19th century, until 2009, when it entered into various mutual defence treaties with the European Union (EU), and other Nordic countries. The policy originated largely as a result of Sweden's involvement in the Napoleonic Wars, during which over a third of the country's territory was lost in the Finnish War (1808–1809), including the traumatic loss of Finland to Russia, which it remained part of until Finland gained independence in 1917. Resentment towards the Swedish king Gustav IV Adolf, who had consistently pursued an anti-Napoleonic policy and thereby caused the war, precipitated a coup d'état known as the Coup of 1809. The new regime deposed the king and introduced the Instrument of Government (1809), later formulating a new foreign policy that became known as The Policy of 1812.

Since the Napoleonic Wars, Sweden has not initiated any direct armed conflict. However, Sweden's military and government have been involved in major peacekeeping actions and other military support functions around the world. The accession to the European Union in 1995 meant that neutrality as a principle was abolished. Sweden remained a non-aligned country in regard to foreign and security policy until joining the North Atlantic Treaty Organization (NATO) in 2024.

Swedish neutrality during World War II has been much debated in the years since. Despite the British naval blockade of Nazi Germany, and the official posturing of the Swedish government, Sweden exported iron ore to supply Nazi Germany's war industry via the Norwegian port of Narvik. The German war industries' dependence on Swedish iron ore shipments was the primary reason for the United Kingdom and its allies to launch Operation Wilfred and the Norwegian Campaign in early April 1940. By early June 1940, the Norwegian Campaign stood as a failure for the Allies, and by securing access to Norwegian ports by force, the Nazis were able to obtain the Swedish iron ore it needed for war production, even with the British naval blockade still in place. Sweden also supplied the Nazi German war industry with steel and machined parts throughout the war and provided transportation for armed German reinforcement troops, the 163rd Infantry Division/Division Engelbrecht commanded by General Erwin Engelbrecht, and military equipment through Swedish territory by train from Norway to the eastern front in Finland.

Sweden maintained its policy of neutrality after World War II, despite substantial cooperation with the West. Former Prime Minister of Sweden Carl Bildt has noted that this policy was in response to fears that if Sweden were to join NATO the Soviet Union might respond by invading Finland, with which Sweden retained close relations.

In 2022, Sweden applied to join NATO. Sweden became the 32nd member of NATO on 7 March 2024.

The new foreign policy, often called The Policy of 1812, was directed by Jean Baptiste Bernadotte, the recently elected Crown Prince, who had served as Regent since 1811. The policy of 1812 was in sharp contrast to Sweden's previous foreign policy, during which Sweden had been involved in many conflicts, especially with its arch enemy, Russia. However, in 1812, with Napoleon starting a campaign against Russia and Emperor Alexander, the Emperor was in need of allies, and so met with the Swedish Crown Prince in Åbo. At the meeting it was agreed that Sweden would accept that Finland was part of Russia in exchange for the Tsar's help in pressuring Denmark to cede Norway to Sweden.

Swedish troops led by Bernadotte took part in the Napoleonic Wars in 1813 and 1814, wherein the Crown Prince authored the Allied Campaign Plan, known as the Trachenberg Plan, and commanded the Allied Army of the North. Bernadotte's army fought against the French in the fall of 1813 and defeated them at the Battle of Grossbeeren, Battle of Dennewitz and played a key role in the mammoth Battle of Leipzig. Bernadotte then led an invasion of Denmark. Sweden forced Denmark to hand over Norway by the Treaty of Kiel. This was recognised by the Allied powers at the Congress of Vienna. Since this time Sweden has not taken part in armed warfare (with the exception of peacekeeping).

During the First War of Schleswig, from 1848 to 1851, Swedish troops were located in Jutland^{[citation needed]} as support for Denmark against Prussian-supported rebels; the Swedish regular troops, however, never experienced any combat. Hundreds of Norwegian and Swedish volunteers joined and fought in the Danish army.