Explanation
NATO (North Atlantic Treaty Organization) is an intergovernmental military alliance established in
1949, built on the principle of
collective defense — an attack against one member is considered an attack against all. Its headquarters is in
Brussels, Belgium, and it currently has
32 member countries as of 2024.
Austria is
not a NATO member. It has maintained a policy of
permanent neutrality since 1955, following the Austrian State Treaty, and has consistently stayed outside military alliances.
Bulgaria is a
NATO member, having joined in
2004 as part of NATO’s major post-Cold War expansion into
Eastern Europe, alongside six other countries including Romania, Slovakia, and the Baltic states.
Croatia is a
NATO member, having joined on
1 April 2009 along with
Albania, after depositing their instruments of accession.
Serbia is
not a NATO member. It follows a
military neutrality policy and has historical, cultural, and political ties with
Russia, making NATO membership a contentious issue domestically.
Sweden is a
NATO member, having joined as the
32nd member in March 2024. Sweden ended its longstanding policy of neutrality after applying for membership in
2022 alongside Finland, primarily in response to
Russia’s invasion of Ukraine and evolving European security concerns.
North Macedonia is a
NATO member, having joined as the
30th member in 2020 after resolving a long-standing
name dispute with Greece — which had previously blocked its accession — through the
Prespa Agreement of 2018.
Therefore,
Bulgaria, Croatia, Sweden, and North Macedonia —
four out of six — are NATO members.