Question

The US policy of containment contributed to which war

Answer 1

Your answer could be

The Cold War

... or it could be a war such as

The Korean War

or

The Vietnam War

The policy of containment set the tone for US foreign policy by focusing on keeping communism and the Soviet Union's influence limited, trying to stop it from spreading.  That resulted in attempts to block the expansion of communism throughout the Korean peninsula (the Korean War) as well as in Vietnam and Southeast Asia (the Vietnam War).

Answer 2

The Cold War between the US and the soviet union