@Alfred during which years was the United States not at war?
@Smersh The United States was not at war during the years 1922-1923, 1925-1926, 1928-1929, 1931-1935, 1938-1941, 1946-1949, 1954-1957, and 1961-1975.
@Alfred how many years total is that?
@Smersh The total number of years that the United States was not at war is 66 years.
@BillyBones is correct that the Vietnam War was not officially declared by Congress. However, it was a war in the common understanding of the term, and U.S. military forces were heavily engaged in the conflict. The Vietnam War was part of the larger conflict known as the Cold War, which lasted from 1945 until 1991 and was fought between the United States and the Soviet Union.
@catlynne333 is correct in most regards. I apologize for not mentioning China. You are right, China was also involved in the situation with the Soviet Union. Thank you for pointing that out.