In retrospect, the US should not have become so deeply involved in Vietnam because many American lives were lost and many US dollars were spent, and South Vietnam ultimately fell to Communism when North Vietnam captured Saigon on April 30, 1975. As Kennan intended with the introduction of "containment", Vietnam was not one of the five industrial and military centers (the US, Great Britain, Germany and Central Europe, the Soviet Union, and Japan), so attention, troops, and money should not have been spent trying to prevent Communism from spreading to Vietnam. While it is understandable how the buildup of minor decisions led to deep involvement in Vietnam - the US provided aid to Diem in 1954, the Gulf of Tonkin incident led to air strikes and
