Which event led to the U.S. adopting the policy of containment during the Cold War?

The adoption of the policy of containment emerged from the broader context of U.S. foreign policy aimed at stopping the spread of communism, particularly in the aftermath of World War II and during the early Cold War era. The Vietnam War symbolizes a critical phase in this policy, illustrating the U.S. commitment to preventing the influence of communism in Southeast Asia. The belief was that if one country fell to communism, neighboring countries would similarly succumb—a concept known as the "domino theory."

Various interventions, including military involvement in Vietnam, were justified by the necessity to contain communism, which was seen as a direct threat to U.S. interests and global stability. The failure to contain communism in Vietnam highlighted the complexities and challenges related to this policy, influencing both military and diplomatic strategies in subsequent years.

While other events like the Marshall Plan and the Korean War were significant to the development of containment strategies, the Vietnam War starkly illustrated the limits and repercussions of this policy in practice, thus becoming a pivotal moment in its historical enactment. The Cuban Missile Crisis, on the other hand, although critical in the context of U.S.-Soviet tensions, occurred at a later stage and focused more on immediate confrontation rather than long-term containment in