What is the primary military alliance formed to counter Soviet influence during the Cold War?

The primary military alliance formed to counter Soviet influence during the Cold War is NATO (North Atlantic Treaty Organization). Established in 1949, NATO was created as a collective defense mechanism among its member states in North America and Western Europe. The main purpose of NATO was to provide mutual defense against aggression, particularly aimed at the threat posed by the Soviet Union and its satellite states during the Cold War era.

NATO functions on the principle that an attack against one member is considered an attack against all, which fosters a strong deterrence strategy against the expansion of Soviet power in Europe. This collective security arrangement was pivotal in the military and political framework of the Western alliance throughout the Cold War, shaping international relations and contributing to the eventual collapse of Soviet influence in Eastern Europe.

Other alliances like SEATO and ANZUS were formed for different regional concerns and did not have the same primary focus on countering Soviet influence in Europe. The Warsaw Pact, on the other hand, was a response from the Soviet side to counter NATO and establish a bloc of Eastern European countries under Soviet control. Thus, NATO remains the most significant military alliance in this context.