Russia’s invasion and full-scale war against Ukraine caused a change in Finland’s traditional security policy of military non-alignment.

Ever since 1994, Finland had participated in NATO’s so-called Partnership for Peace program and had benefited from it, e.g. in strengthening the country’s own defence capability. NATO compatibility was also promoted through participation in many NATO exercises and NATO-led crisis management operations.

Starting from the late 1990s, Government Reports on Foreign and Security Policy stated that Finland was prepared to apply for NATO membership if the security situation deteriorated substantially. Russia’s large-scale invasion of its neighbour, Ukraine, was such a factor that was seen as weakening Finland’s security. The attack indicated that the Russian leadership was ready to ruthlessly use military force as an instrument of foreign policy.

The war started by Russia came as a great shock to Finns. For decades, Finland had trusted that a cautious foreign policy and military non-alignment would ensure the country’s security. Popular support for joining NATO began to grow strongly. After Russia’s invasion began in February 2022, support for joining NATO rose to 53 % and the percentage opposing it fell to 28 %. In March, the respective figures were 62 % and 16 %, and in May 76 % of people were in favour of joining NATO and only 12 % were against.

The rapid turning of popular opinion in favour of NATO membership convinced the state leadership that change was necessary. The President and the Government began preparations for applying for NATO membership. The Government maintained close contact with Sweden, as the Swedish government was also preparing to apply for NATO membership and the goal was a parallel NATO process in both countries.

The application for NATO membership was done in strict accordance with the Constitution. The Government published a Report on changes in the security environment, detailing the security factors, especially the growing threat from Russia, and the security to be gained from NATO membership. During the parliamentary reading of the Report, most parties and MPs were in favour of joining NATO. On 17 May 2022, Parliament voted in favour of applying for NATO membership (188 in favour, 8 against, 3 absent). The membership application was submitted to NATO Headquarters in Brussels on 18 May 2022.

At the NATO summit in Madrid in June 2022, Finland and Sweden were invited to join NATO as observer members. After ratification of the accession protocols, Finland became a member of NATO with full rights and obligations on 4 April 2023.