Which of these did NOT lead to the end of U. S. involvement in Vietnam?

The last U.S. combat troops leave South Vietnam as Hanoi frees the remaining ... America's direct eight-year intervention in the Vietnam War was at an end. ... In response, Johnson announced in March 1968 that he would not seek reelection, ... This expansion of the war, which accomplished few positive results,

Explanation:

operation overlord was the codename for the battle of normandy, the allied operation that launched the successful invasion of german-occupied western europe during world war ii. the operation was launched on 6 june 1944 with the normandy landings