August 27, 2008 marked the 100th anniversary of the birth of the 36th president of the United States, Lyndon Baines Johnson. Although LBJ was the architect of some of the most sweeping social legislation of the 20th Century, his legacy has been overshadowed by a war that ultimately drove him from office.

"Johnson is a mixture of huge achievements and tragic failures," one of his former speechwriters, Harry McPherson, told "War Stories." "It has become politically dicey for politicians to talk about Lyndon Johnson, because for many people, Lyndon Johnson equals Vietnam."

Although he was a seasoned and skillful politician, his reputation has been so tarnished by Vietnam that Johnson's name has never been mentioned at any Democratic Convention since 1968. "He just has become the invisible president," says former Johnson aid Lloyd Hand.

But it wasn't always that way.

Catch 'The Life and Times of Lyndon Baines Johnson,' Sunday, May 24 at 3 p.m. ET

When John F Kennedy was assassinated in Dallas in 1963, Vice President Lyndon Johnson was catapulted into the presidency and, in the dark days that followed, LBJ proved to be a steadying force for a country desperate for leadership.

"I would argue that the greatest contribution Johnson made to his country," says McPherson, "was by re-establishing the confidence of people in the government, by conveying to the world that the United States was in the hands of a President who was enormously competent." His landslide victory over Arizona Republican Barry Goldwater with an unprecedented 61 percent of the popular vote in the 1964 presidential election was a testament to his initial popularity.

With a mandate from voters, Johnson declared a war on poverty and discrimination that would serve as the cornerstone of what he envisioned as the "Great Society." An unprecedented amount of legislation was pushed through Congress in the first two years of the Johnson administration. The Civil Rights Act of 1964 made racial discrimination illegal. Medicare was created to provide health care services to the elderly, while Medicaid helped the poor. The 1965 Voting Rights Act guaranteed that no person would be denied the right to vote on account of race or color.

"He said it was the greatest piece of legislation that passed," says former Secretary of Health, Education and Welfare Joseph Califano, who was also an assistant to LBJ. "All you have to do is look at America today. We have this tremendous increase in desegregation in this country."

But it was the escalation of the war in Vietnam that proved to be Johnson's undoing. "I think that Vietnam tore the fabric of our country apart so badly," says Lloyd Hand. "I think it's affected our foreign policy ever since and I think it's affected the way people have viewed Lyndon Johnson."

LBJ ran as the "peace candidate" in 1964, pledging not to send more "American boys 9 or 10,000 miles away from home to do what Asian boys ought to be doing for themselves." But by the end of 1965, 200,000 troops were on the ground in Vietnam, a number that would double to 400,000 by the end of 1966.

"Johnson wanted to protect the Great Society legislation, and not force a choice between domestic spending and war time spending, and not have a debate on Vietnam," says H.R. McMaster, the author of "Dereliction of Duty." "This was not only un-Democratic, it removed what could have been an important corrective to an unwise policy."

"Hey, hey, LBJ! How many kids did you kill today?" became the mantra of the growing anti-war movement. The war in Vietnam became so divisive that by March of 1968 Johnson had decided not to seek re-election.

"I said, but you have to run," remembers McPherson, who had lunch with Johnson and Joseph Califano in the White House Rose Garden a few weeks before Johnson stunned the nation with his announcement. "He said, 'Why?' And I said, 'I think you're the only one who can get anything done.' And he said, 'No, you've got it exactly wrong, I'm the only one who can't.'"

"He said the Congress and I are like an old married couple that's been married about 50 years," remembers Califano, "And they're just tired of rubbin' up against each other in bed every night."

"He was very, very philosophical about what had happened," says Harry Middleton, a former LBJ speechwriter and director emeritus of the LBJ Library. "He said, 'You know, we've been pretty well discredited. And we've got to recognize that. And things are gonna change, history will change, but right now, the country is divided over Vietnam, and the country feels well rid of us.'"

Steven Tierney is a producer for "War Stories"