In the spring of 2017, I found myself sitting on a lawn outside a modest hotel in Mill Valley, California, with Dennis Banks, the legendary founder of AIM (American Indian Movement), and Sacheen Littlefeather, the Native American actress-activist who, in 1973, turned down the best-actor Oscar on behalf of Marlon Brando, in protest against Hollywood’s racist depiction of Indians.

Inside the hotel conference room, a few dozen veterans of AIM’s militant actions of the 1970s were gathering to celebrate Banks’s 80th birthday. There was a sense of wonder that this “red giant”—as one former AIM warrior called him—had survived the fires of his volcanic past. Here he was after eight decades, still among us, looking fit and cool in his porkpie hat, wire-rimmed dark glasses, embroidered vest, turquoise bolo tie, and black jeans. Before the year was over, Banks would be dead, succumbing to complications from open-heart surgery. But today the “Ojibwa Warrior” (also the title of his 2004 memoir) was triumphant and in a mood to relive the glories and traumas of his revolutionary life.

Banks and other Wounded Knee occupiers withstood more than 500,000 rounds of ammunition during the government’s seven-week siege, in 1973.

I was interviewing Banks for my upcoming book, By the Light of Burning Dreams (co-authored with my sister Margaret Talbot), which recounts dramatic turning points in the lives of radical leaders of the “second American Revolution,” in the 1960s and 1970s.

Banks spoke mainly that day about the stormy, 71-day occupation of Wounded Knee, in 1973, during which more than 300 heavily armed F.B.I. agents, federal marshals, and vigilantes surrounded some 200 AIM activists and residents of the Pine Ridge Reservation. AIM and local Oglala Lakota tribespeople had seized the forlorn outpost on the snowy plains of South Dakota, where in December 1890 as many as 300 of their tribal ancestors—men, women, and children—had been massacred by the U.S. Seventh Cavalry, the regiment once commanded by the ruthless George Custer. Banks and his followers, who were protesting the long history of broken federal treaties and the corruption of reservation officials, said that at night they could hear the moans and cries of the Seventh Cavalry’s victims.

Indian leader Russell Means, left, was charged with 10 felonies following Wounded Knee. Here, Marlon Brando attends court in solidarity with the American Indian Movement.

The Wounded Knee occupiers withstood more than 500,000 rounds of ammunition during the seven-week siege, much of it fired from military-grade weaponry. Littlefeather talked about closely coordinating her controversial Academy Awards appearance, which took place in the middle of the siege, with Brando, a strong AIM supporter, and Banks, in order to refocus the media spotlight on Wounded Knee and prevent more casualties. (Remarkably, only two Native warriors died from the withering gunfire.)

Banks spoke about his heart-pounding escape from Wounded Knee on the last night of the AIM stand. His supporters feared he would suffer the fate of Sitting Bull or Crazy Horse—the two Native heroes who had died the previous century at the hands of federal agents. Instead, Banks miraculously slipped past the armored vehicles, trip wires, and vicious guard dogs that encircled the camp, led by a young Navajo scout named Lenny Foster, so he could live to fight another day. Which he did for more than four decades.

The Nixon Secret

I knew some of this dramatic story from reading Banks’s memoir and interviewing Foster. But on that afternoon, as his 80th-birthday party was taking off inside the hotel, the AIM leader related an encounter in the aftermath of Wounded Knee that I’d never heard before. It’s an astounding story with historic implications, and upon hearing it I once again marveled about how the past is a series of doors that lead to other locked doors.

Nixon advisers John Ehrlichman and H. R. Haldeman on Air Force One, April 1973. They would resign three days later.

In 1974, about a year after the Wounded Knee showdown, Banks revealed to me, he was asked to attend a secret meeting with H. R. “Bob” Haldeman and John Ehrlichman, who until the spring of the previous year had served as President Richard Nixon’s top White House aides. So protective were Haldeman and Ehrlichman of Nixon that White House Counsel John Dean called them the “Berlin Wall.”

By 1974, both Nixon loyalists, who had resigned from the White House in a desperate effort to save the Nixon presidency, were awaiting trial on charges connected to the Watergate scandal, for which they would both be convicted in January 1975 and serve 18 months in federal prison. Considering their closeness to Nixon, whose armed siege of Wounded Knee had become a searing moment in Native American history, Haldeman and Ehrlichman’s willingness to meet with the militant AIM leader was astonishing in itself. But equally surprising was the host of the sit-down, none other than Marlon Brando, at whose Mulholland Drive home, perched high above Beverly Hills, the meeting took place.

Haldeman and Ehrlichman wanted to deliver an important message to Banks that day. He was still alive—as were nearly all of the other Native warriors who took a stand at Wounded Knee—because of President Nixon’s restraint. Near the end of the siege, according to the former White House aides, Justice Department and F.B.I. officials had met with Nixon and presented a shocking plan to terminate the occupation by invading the camp with overwhelming force.

Ehrlichman and Nixon, 1972.

“Nixon’s men told me that the F.B.I. wanted to lay down a blanket of gas from helicopters,” said Banks. “And then they were going to come in with arms and retake it.”

But an outraged Nixon quashed the bloody plan, according to his former deputies. “They said Nixon was very angry,” Banks told me. “The president said, ‘You mean to tell me that a group of ragtag Indians has got the whole Justice Department and the F.B.I. and the U.S. Marshals running scared? That you want to use gas and bullets to end this? Not on my watch.’”

This coolheaded picture of Nixon conflicts with his historical image. And, as we point out in By the Light of Burning Dreams, he might have been nursing one of his deep grievances by accusing the F.B.I. of attempted overkill at Wounded Knee. As the Watergate scandal escalated, the president grew increasingly estranged from the F.B.I. and C.I.A., blaming the agencies for not rescuing him from his quandary. Indeed, Mark Felt, the F.B.I.’s No. 2 official during the Nixon presidency, later revealed himself to be “Deep Throat,” the Watergate whistleblower for The Washington Post’s Bob Woodward and Carl Bernstein.

Singer Harry Belafonte, who attended the Wounded Knee trial with Banks, compared the position of the American Indian Movement to that of Black civil-rights organizations in the 1960s.

But Banks himself clearly believed what Haldeman and Ehrlichman told him that day at Brando’s house. The AIM leader reminded me that Nixon’s mentor at Whittier College was his Native American football coach, Wallace “Chief” Newman, who continued to give advice to Nixon throughout his political career. “I think I admired him more and learned more from him than any other man aside from my father,” Nixon wrote in his memoir RN. “He drilled into me a competitive spirit and the determination to come back after you have been knocked down or after you lose.”

“Nixon was the only sitting president to give land back to the Indian people,” Banks told me.

If Nixon was an unsung supporter of Native Americans, Brando was an overt advocate of Indian rights, and more than once came to Banks’s rescue. In 1975, after Nixon had been driven from the White House, the AIM leader again found himself at the actor’s Mulholland Drive aerie, on the run from the law. Brando gave Banks his motor home and $10,000 in cash—much of which he used to buy an arsenal for AIM warriors to defend themselves on the increasingly violent Pine Ridge Reservation and other battlegrounds. After a tense confrontation with state troopers on Interstate 84 near the Oregon-Idaho border, Banks bailed out of Brando’s motor home while fleeing down the highway—and the expensive vehicle ended up an incinerated shell after lawmen finished with it. But the AIM warrior remained friends with Brando until the actor’s death, in 2004, despite the legal jeopardy in which he put the movie star.

Banks and Brando in New York City.

By his 80th birthday, Dennis Banks was no longer running. Now a legend in his own time, he smiled warmly as he made his way through the crowd of well-wishers at the hotel party, where the smell of burning sage added to the nearly spiritual mood of the occasion. Robby Romero, a Native activist who was part of Banks’s entourage that day, recalled the aging leader’s visit the year before to Standing Rock, the greatest display of Indian resistance since Wounded Knee—a protest camp where firearms were strictly prohibited this time. “He was a hero to all the water protectors at Standing Rock,” Romero recalled. “Walking through the camp, so many people came up to him, I thought, ‘My God, we’ll never get to our tepee.’

“But Dennis had a calming effect on people, these young warriors who were on the front lines at Standing Rock and were being beaten and shot by rubber bullets and Tasers and pepper spray. They had no weapons, just prayer. And Dennis explained to them why taking a nonviolent role was important and the difference between Wounded Knee and Standing Rock.”

You live to fight another day.

David Talbot is the author of The Devil’s Chessboard and Brothers, and a co-author of the forthcoming By the Light of Burning Dreams: The Triumphs and Tragedies of the Second American Revolution, publishing June 8 from Harper