The Vietnam War had a profound impact on U.S. foreign policy, fundamentally altering its approach to international conflicts. Initially, America engaged in Vietnam to prevent the spread of communism as part of the broader Cold War strategy. However, the war's unpopularity and the significant loss of lives led to widespread public protest and a reevaluation of U.S. interventionist policies. Following the war's conclusion in 1975, American foreign policy transitioned towards détente, focusing on diplomacy over military engagement. The experience influenced future U.S. actions in conflicts, leading to a more cautious approach, emphasizing multilateralism and the importance of public support in military interventions.