Hope makes history. So does betrayal of hope.

Early in his presidency, Lyndon Johnson inspired enormous hope. But the promise for a Great Society imploded — and disappointment jolted many former supporters, with trust and optimism turning into alienation and bitterness. The negative ripple effects lasted for decades.

Fifty years after Johnson entered the White House, the corrosive aspects of his legacy are easy to discern. A political base for progressive social change eroded as he escalated the Vietnam War and bought time with shameless deceit. For many people, distrust of leaders became the essence of realism.

Initiating a disastrous mix of rhetoric and carnage, Johnson told the nation on Aug. 4, 1964, “We still seek no wider war.” On the same day, he ordered bombing of North Vietnam in tandem with bogus claims that its navy had attacked U.S. ships in the Tonkin Gulf.

Throughout his full term after a landslide victory in the November 1964 election, LBJ continued to claim benign intent in Vietnam. “I do not genuinely believe that there’s any single person anywhere in the world that wants peace as much as I want it,” Johnson said on May 17, 1966. In mid-January 1968, he insisted that “our goal is peace — and peace at the earliest possible moment.”

For many citizens, the president’s willingness to lie while pursuing indefensible policies caused massive — and perhaps irreversible — distrust and even enmity toward the U.S. government. As a consequence, millions came to see history and current events in a starkly clearer light. By the time Jimi Hendrix performed the national anthem at Woodstock five years after Johnson’s Gulf of Tonkin speech, an unprecedented number of Americans heard the musical bombs bursting in air as horrific instead of noble.

Forty years later, the new presidency of Barack Obama was awash in a strong tide of good will, comparable, in its own way, to the wave of public sentiment that lifted Johnson as the new president after the Nov. 22, 1963, assassination of John F. Kennedy. Obama had run and won on hope, and his victory — while not of Johnson’s landslide proportions — provided major momentum.

Obama pursued policies that largely undercut his lofty oratorical appeals to his base. Deference to corporate power, the military-industrial complex and the national-security surveillance state — coupled with scant action on the vastly important matter of climate change — turned him into another president eager to cater to the intersection of Wall Street and Pennsylvania Avenue.