Which Asian nation experienced a military loss for the US in its efforts to contain communism?

Vietnam is recognized as the Asian nation where the United States experienced a significant military loss in its efforts to contain communism. The Vietnam War was a protracted conflict beginning in the late 1950s, with the U.S. deeply involved by the 1960s, aiming to prevent the spread of communism from North Vietnam to South Vietnam as part of its broader Cold War strategy.

The U.S. employed extensive military resources and personnel; however, despite considerable efforts, including bombings and ground troops, the conflict ended in 1975 with the fall of Saigon and the reunification of Vietnam under communist control. This outcome represented not only a military defeat for the United States but also a significant psychological and political setback in the context of Cold War dynamics.

In contrast, China's transformation in the mid-20th century led to a communist regime, but the U.S. did not engage militarily in a war with China during the civil war that established the People's Republic of China. The Korean War involved a military confrontation, but it ended in a stalemate with the establishment of a divided Korea rather than a clear defeat. Japan, under U.S. influence after World War II, became an ally and did not experience a military conflict against the