Who were the 4 american presidents in office some time during the vietnam conflict?

As the Vietnam War lasted from 1955 to 1975, there were not 4 but 5 American presidents in office during that time. They were:

-Dwight D. Eisenhower, who was president from 1953 to 1961, although American intervention in the war hadn't started at his time in office.

-John F. Kennedy, American president from 1961 until his murder in 1963. During his term, American advisors were sent to Vietnam but there was no direct intervention.

-Lyndon B. Johnson, whose term lasted from 1963 to 1969. He started the direct intervention in the war in 1964, after the Gulf of Tonkin incident.

-Richard Nixon, President of the United States from 1969 to 1974, he led the process of Vietnamization, and the retirement of American troops from the war.

-Gerald Ford, whose term lasted from 1974 to 1977. During his term, American intervention in the war was over, but the conflict lasted until 1975, when North Vietnam defeated South Vietnam.