It could be argued that LBJ accomplished the most, if a negative way is construed to mean "accomplished." President Johnson brought North Vietnam & the US into direct open warfare in 1964. Prior to that time, the Vietnam War was only a guerrilla war restricted to South Vietnam.
Little argument will be made stating that Nixon accomplished the most in Vietnam. Nixon feared nothing and mounted the most devastating aerial attacks upon another nation in military history (Operations Linebacker & Linebacker II). Nixon also openly attacked "into" a foreign nation (twice); Cambodia in 1970 & and Laos in 1971, then got American POWs returned. He then declared victory and sent us home. Kind of hard to beat those accomplishments.
Probably the most important citizen of Vietnam during the Vietnam War period was Ho Chi Minh. He was the president of North Vietnam and considered a hero to many.
I would say the North Vietnamese and their leader Ho CHi MInh. They defeated the French, the Americans and the South Vietnamese , conquered all of Vietnam and pretty well accomplished all their objectives. Of course, they paid a big price in loss of life and money.
Kennedy added more "advisers", Johnson drafted the most men and sent in the most of the troops, and Nixon expanded the war with his secret bombings into Laos. So, the three of them escalated it bit by bit. Despite the acts of President Nixon, he had run for president on the promise to end the Vietnam War. This he accomplished.
President Johnson believed that the US could defeat north Vietnam because the US had won WWII with firepower, and the US had the most firepower on earth during the Vietnam War.
The most effective us president is Abhraham Linkhan
The preservation of classical texts during the Middle Ages was most often accomplished in monasteries.
The most common request made by US commanders during the Vietnam War, was a constant request to the President for: More men. (40,000 men a month were being drafted by 1968). This was called the "escalation of the war."
Giap was the most known.
Granting amnesty to America who evaded the Vietnam draft by President Jimmy Carter was called the most disgraceful thing a president has ever done.
Lyndon Johnson authorized this and most of the military operations in Vietnam.
LBJ sent the most. In 1968 it was the largest draft.
The war began when President Eisenhower sent US Advisers to Vietnam in 1955; however most historians consider the starting date of the war to be 1961, when President Kennedy sent the Special Forces (Green Beret) to Vietnam.