Collective defence

NATO's central principle was collective defence: an attack on one member would be regarded as an attack on all. This was intended to deter aggression by warning a potential attacker that it would face an alliance rather than an isolated country. It also committed the USA to Western European security in peacetime.

NATO was based on collective defence: an attack on one member would be treated as an attack on all. Its members intended this commitment to deter Soviet aggression by making clear that an attacker would face a united response. Stalin, however, interpreted NATO as an aggressive alliance directed against the Soviet Union.