On April 30, 1975, when the last helicopter lifted off the roof of the U.S. Embassy in Saigon, the Vietnam War, the most consequential event in American history since World War II, ended in failure. More than 58,000 Americans and as many as 3 million Vietnamese had died in the conflict. America’s illusions of invincibility had been shattered, its moral confidence shaken. The war undermined the country’s faith in its most respected institutions, particularly the military and the presidency. The military eventually recovered. The presidency never has.

It did not happen all at once, this radical diminution of trust. Over more than a decade, the accumulated weight of critical reporting about the war, the publication of the Pentagon Papers in 1971, and the declassification of military and intelligence reports tarnished the office. Nor did the process stop when that last chopper took off. New evidence of hypocrisy has continued to appear, an acidic drip, drip, drip on the image of the presidency. The three men who are most responsible for the war, John F. Kennedy, Lyndon B. Johnson, and Richard Nixon, each made the fateful decision to record their deliberations about it. The tapes they left behind—some of them still newly public, others long obscured by the sheer volume of the material—are extraordinary. They expose the presidents’ secret motives and fears, at once humanizing the men and deepening the disillusionment with the office they held.

For most of American history, that office conveyed authority, dignity, and some measure of majesty upon its occupant. The great presidents—Washington, Jefferson, Lincoln, the Roosevelts—came to be viewed not merely as capable executives but as figures of myth: They were heroic, selfless, noble, godlike. Time has a way of burnishing reputations. But as late as the middle of the last century, Americans were inclined to view even incumbent presidents with reverence. Faith in the presidency may have reached its apogee soon after the Second World War. The public generally trusted Harry Truman and Dwight Eisenhower to be honest and well intentioned and to put the interests of the nation above their own.

It is no coincidence that the last president to inspire such trust was also the last president elected before the Vietnam War began in earnest. Kennedy’s charisma, and his military bona fides, encouraged Americans to believe in their young president as he confronted a complicated and dangerous world. His promise, in his inaugural address, that the United States would “pay any price, bear any burden, meet any hardship, support any friend, oppose any foe, to assure the survival and the success of liberty” reinforced Americans’ vision of their country as a muscular force for good around the globe.

As president, Kennedy immediately faced the challenge of how to use that power. He refused to send American troops to secure a pro-Western government in Laos. But after the Bay of Pigs fiasco, and having been bullied by Soviet Premier Nikita Khrushchev at a summit in Vienna, he made a different calculation when it came to the continuing crisis in Vietnam, one influenced by domestic political concerns. Kennedy confided to an aide: “There are just so many concessions that one can make to the Communists in one year and survive politically.” With the Vietcong gathering strength in South Vietnam, he felt he had to act.

If not for his untimely death, Kennedy’s legacy might have been sullied while he was in office. Instead, not until the Pentagon Papers were published did Americans discover that he and his administration had harbored misgivings about the political and military progress in Vietnam but never shared their reservations with the public, even as they steadily increased America’s commitment of special forces and military “advisers.”

In August 1963, disturbed by the authoritarian South Vietnamese President Ngô Đình Diêm’s failure to win over the populace or thwart the Communist insurgency, Kennedy approved a plan to encourage a cabal of dissident generals to overthrow Diêm’s regime. In November, rebel troops seized key installations in Saigon and promised Diêm and his ruthless brother Ngô Đình Nhu safe passage out of the country. As soon as the brothers surrendered, they were murdered by rebel leaders. South Vietnam plunged into chaos, and a bad situation got worse.

On November 4, 1963, shortly after the coup, Kennedy recorded his thoughts about what he had allowed to happen. The Kennedy who speaks on this rarely heard tape is not the bold young man of the inaugural address, but a president consumed by doubt, even remorse. He rues having made such a crucial decision without adequate consideration.

Over the weekend the coup in Saigon took place. It culminated three months of conversation … which divided the government here and in Saigon … I feel that we must bear a good deal of responsibility for it, beginning with our cable of … August in which we suggested the coup … I should not have given my consent to it without a roundtable conference … I was shocked by the death of Diêm and Nhu … The question now is whether the generals can stay together and build a stable government or whether … public opinion in Saigon … will turn on this government as repressive and undemocratic in the not-too-distant future.

Listen to John F. Kennedy:Edited audio courtesy Vietnam Film Project/Florentine Films, PBS, and the Miller Center.

Kennedy did not live to learn the answer to his question. He was murdered in Dallas 18 days later.

Lyndon Johnson inherited both the presidency and the rapidly deteriorating situation in Vietnam. As vice president, he had opposed the Diêm coup, and he now dreaded being drawn more deeply into the conflict. He hoped the South Vietnamese would “get off their butts and get out in those jungles and whip hell out of some Communists,” he told an aide. “And then I want ’em to leave me alone, because I’ve got some bigger things to do right here at home.” Yet, like Kennedy, he allowed political calculations to affect his approach to the war.

It was not until the 1990s that most of the Johnson recordings began to be processed, digitized, and made accessible to the public—they are still not fully transcribed, and some remain classified. But the 700 mesmerizing hours of tape that are available cast new light on the inner workings of his presidency. In public, Johnson confidently reassured the country that the war in Vietnam was going well. Privately, his frustrations and misgivings were on excruciating display. In May 1964, less than six months before the presidential election, Johnson confessed to National-Security Adviser McGeorge Bundy that he did not know what to do.

johnson: I just stayed awake last night thinking about this thing—the more I think of it, I don’t know what in the hell … It looks like to me we’re getting into another Korea. It just worries the hell out of me. I don’t see what we can ever hope to get out of there with once we’re committed … I don’t think it’s worth fighting for and I don’t think we can get out. And it’s just the biggest damn mess I ever saw.

bundy: It is, it’s an awful mess …

johnson: I just thought about ordering those kids in there, and what in the hell am I ordering [them] out there for?

bundy: One thing that has occurred to me—

johnson: What the hell is Vietnam worth to me? … What is it worth to this country? …

bundy: Yup. Yup.

johnson: Now, of course, if you start running the Communists, they may just chase you right into your own kitchen.

bundy: Yup. That’s the trouble. And that is what the rest of that half of the world is going to think if this thing comes apart on us …

johnson: It’s damned easy to get in a war, but it’s going to be awfully hard to ever extricate yourself if you get in.

Listen to Lyndon B. Johnson and McGeorge Bundy:Edited audio courtesy Vietnam Film Project/Florentine Films, PBS, and the Miller Center.

Johnson’s doubts about whether the war was winnable or worth fighting persisted throughout his presidency. But he could not countenance being seen as the first commander in chief to lose a war. In 1965, Defense Secretary Robert McNamara told the president that even if he committed more men, the chances of victory were no better than one in three. Johnson still decided to escalate.

As American casualties mounted and news filtered back home that the war was not going nearly as well as the White House had been claiming, the public’s faith in Johnson began to wane. Politicians and journalists described a “credibility gap”—the space between the president’s assertions and the facts on the ground. Skepticism eventually gave way to disillusionment with the presidency itself.

Richard Nixon’s presidency carried that process of disillusionment much further. Nixon’s fondness for audio recordings is notorious. We rightly remember that it was transcripts revealing the president’s crude, cutthroat willingness to conceal his crimes that shocked the nation and forced him from office. But we often forget that the war and the Watergate scandal were inextricably intertwined. Before the White House Plumbers botched the break-in at the headquarters of the Democratic National Committee, they attempted to discredit Daniel Ellsberg, who had leaked the Pentagon Papers, by stealing files from his psychiatrist’s office.

When audio of the Nixon tapes eventually became public in 1980—2,658 of the 3,400 hours are now accessible—Americans could hear for themselves just how cynically the president had approached the war. On tape, he is frequently ruthless, amoral, and self-interested. Nixon had promised peace with honor, but as he weighed the consequences of American withdrawal, chief among his concerns was the potential effect on his reelection in 1972 if Saigon fell to the North Vietnamese. Nixon and his national-security adviser, Henry Kissinger, returned to this worry again and again, including on May 29, 1971, in a conversation not released to the public until 1999:

kissinger: The only problem is to prevent the collapse in ’72 … If it’s got to go to the Communists, it’d be better to have it happen in the first six months of the new term than have it go on and on and on.

nixon: Sure.

kissinger: I’m being very cold-blooded about it.

nixon: I know exactly what we’re up to …

kissinger: But on the other hand, if Cambodia, Laos, and Vietnam go down the drain in September ’72, then they’ll say you went into these … You spoiled so many lives, just to wind up where you could’ve been in the first year.

nixon: Yeah.

Listen to Richard Nixon and Henry Kissinger:Edited audio courtesy Vietnam Film Project/Florentine Films, PBS, and the Miller Center.

The revelations of the Nixon tapes destroyed his presidency and further eroded American faith in the office itself. The presidents of the post-Vietnam era have never managed to fully restore that faith, and lately, it seems, confidence in the chief executive is at a new low, even if tape recorders are no longer running in the Oval Office.

But we needn’t succumb to the cynicism often on display in the Vietnam recordings. The war may have robbed America of its innocence, but it also reminded us that the duty of citizens in a democracy is to be skeptical—not to worship our leaders, who have always been fallible, but to question their decisions, challenge their policies, and hold them accountable for their failures.