The membership of European states in NATO is of central importance for security, strategic and historical reasons. NATO is regarded as the most important defence alliance that ensures peace and stability in the Euro-Atlantic area. Here are the main reasons why Europe should be part of NATO: Collective defence and security: NATO's core is Article 5, which states that an attack on a member state is considered an attack on everyone. This provides a crucial shield against external aggression, especially for smaller European states. Deterrent to Russia: Given the threat posed by Russia and the war in Ukraine, NATO is the key guarantor of security in Eastern Europe. It prevents potential attacks on neighbouring countries. US nuclear shield: Europe is militarily dependent on the US in many areas, especially in terms of nuclear deterrence, reconnaissance, intelligence and air transport. A U.S. withdrawal would leave significant capability gaps. Complement to the EU: While the EU primarily promotes economic and political integration, it lacks its own powerful military structure. NATO fills this gap as a pure military alliance. A "strong NATO and a Europe capable of acting" are often seen as complementary. Community of values: NATO unites democratic states.