At the time of President Kennedy’s assassination, about 16,000 American military advisors were in Vietnam. Before Diem’s death, the Kennedy Administration thought it would pull out 1,000 of those men by the end of 1963.
McNamara and Taylor believed U.S. involvement in the volatile political situation could be over by 1965 and recognized
...any significant slowing in the rate of progress would surely have a serious effect on U.S. popular support for the U.S. effort.
But what if U.S. forces were attacked? Would that change the public’s opinion? It had happened before, at Pearl Harbor.
American naval ships were attacked by the North Vietnamese in the Gulf of Tonkin on August 2, 1964. Historians now believe those attacks were in response to U.S. and South Vietnamese espionage along the North Vietnam coast. Whatever the reason for the attack, U.S. military forces did not respond. But when a second attack allegedly took place on August 4th, the course of the Vietnam War changed forever.
The real question is: Was there really a second attack?