Definition
Containment was the central American foreign policy strategy of the Cold War. Its aim was not to roll back communism where it already existed, but to prevent its spread to new countries — to hold the line and let internal pressures eventually weaken the Soviet system.
The idea is credited to the diplomat George Kennan, who argued in the late 1940s that Soviet expansionism could be checked by firm, patient, long-term resistance at every point where it threatened to advance.
Why it matters
How it works
Containment combined several instruments. Economic aid, such as the Marshall Plan, rebuilt war-torn Europe to reduce the appeal of communism. Military alliances such as NATO deterred Soviet pressure. Direct or proxy intervention met communist advances in particular regions.
The policy was debated throughout the Cold War — critics argued it drew the United States into costly and unwinnable conflicts, while supporters credited it with preventing further Soviet expansion until the system collapsed from within in 1991.