NATO enlargement: Sweden and Finland
This briefing explains Finland and Sweden's decision to join NATO and the process involved in them joining the alliance.
Russia’s invasion of Ukraine in February 2022 and the benefit of NATO’s collective defence agreement prompted Finland and Sweden to end decades of neutrality and non-aligned status and seek membership of the Alliance.
NATO invited both countries to join at its Madrid Summit in June 2022; Finland became NATO’s 31st member in April 2023.
Turkey and Hungary delayed their domestic ratification for Sweden over concerns about its support for Kurdish groups.
In early 2024 Turkey, and then Hungary, ratified Sweden's accession protocol. Sweden became the 32nd member of NATO on 7 March 2024.
What is NATO?The North Atlantic Treaty Organisation (NATO) was formed in 1949 with the signing of the North Atlantic Treaty in Washington. The treaty created an alliance of ten European and two North American states, formed to ensure their collective security and preservation and intended to counter the perceived threat from the then Soviet Union.
What is the process for joining?NATO has an ‘open door’ policy and any European country is eligible to join NATO.
NATO works by consensus, meaning every member must agree to invite an aspiring country to join.
This then starts the accession process, which involves each member of the Alliance signing and ratifying the Accession Protocol. The ratification process varies according to each member’s national procedures. Only once the ratification process is complete can the applicant country formally join the Alliance.
When did Finland join?Finland became the 31st member of NATO on 4 April 2023.
When will Sweden join?Sweden joined the alliance on 7 March 2024.
This came after both Turkey and Hungary delayed ratification of Sweden's accession protocol.
Following Turkey’s parliamentary approval of Sweden’s bid in January 2024, Mr Orbán said Hungary supports NATO membership of Sweden. Hungary's Parliament approved Sweden's membership in late February, paving the the way for Sweden to join in March 2024.
How has Russia responded?Russia has long opposed the expansion of NATO. However, President Putin has indicated he sees no threat to Russia if Sweden and Finland join the Alliance. He has said Russia will respond if NATO begins to establish military infrastructure in either of the two nations. Russia has an 830-mile border with Finland.