In his sleep, he imagines that he still works as a researcher at the Rand Corp., advising Pentagon officials on policy, handling classified documents, studying the science of war.
"Being at Rand was the ideal life for me," Ellsberg says, almost as an afterthought. "In my dreams, I am doing classified work, trying to solve social problems."
Over the decades, Ellsberg, 78, hasn't been welcome at Rand. He committed the most startling breach of security in the company's history, walking out on Oct. 1, 1969, with the first briefcase full of classified documents destined for public release.
That bold move -- and the actions that followed to get them published -- are the subject of a new documentary film, The Most Dangerous Man in America: Daniel Ellsberg and the Pentagon Papers.
The movie had its West Coast premiere only a few blocks from Rand. Ellsberg, ever the agitator, sent college students with flyers to headquarters to urge his former colleagues to attend the screening and try to understand why he did what he did.
None came. Ellsberg acknowledges that some wounds never heal. At a Rand reunion several years back, no one would shake his hand. When he tried to visit Rand, a non-profit think-tank providing analysis of public issues for government agencies, he was escorted out by security guards.
He had read the 7,000-page study of the Vietnam War known as The Pentagon Papers and became convinced that the history of U.S. involvement dating back to 1945 was a study in lies. He wanted to end the war and, although to this day he does not take credit for that, he says his actions and those of other anti-war activists helped shorten the conflict.
The film by Judith Ehrlich and Rick Goldsmith suggests his actions triggered the Watergate scandal and drove President Richard Nixon from office. There are audio tapes of Nixon railing against Ellsberg as a traitor in conversations with Henry Kissinger, who called Ellsberg "the most dangerous man in America."
The release of the classified study in The New York Times and in other newspapers triggered one of the most important First Amendment legal battles the country has ever seen and led to a powerful U.S. Supreme Court ruling for freedom of the press.
Both Nixon and Kissinger were convinced that Ellsberg had more secret documents he planned to release and they launched an offensive that included a break-in at his psychiatrist's office and culminated in his espionage trial in Los Angeles.
The charges were dismissed and a mistrial declared because of "outrageous governmental misconduct," including the break-in and disclosures that the judge had met with Nixon during the trial and was offered the job of FBI director.
All of it is depicted in the film, which is billed as a combination political thriller and love story. Early reviews have been positive.
At Ellsberg's side is his wife, Patricia, his greatest ally in his long political odyssey.
"Many people come up to me and say, 'Your husband is my hero,"' she says. "I can say after almost 40 years of marriage, he is my hero. He embodies patriotism and a higher loyalty than to an institution or a policy."
Ellsberg has been arrested for acts of civil disobedience 78 times and she has also been taken off to jail for demonstrating, she says.
"The transformation Dan went through is the transformation our society needs to go through," she says during a question-and-answer session after a screening.
Ellsberg travels the country speaking, protesting and urging others to do what he did -- leak important information that reveals government untruths. He talks about the American involvement in Iraq and Afghanistan, saying the latter has the potential to become "Vietnamistan" if the U.S. increases troops there.
Ellsberg remains a study in contradictions: He is a former Hawk on the war who risked everything for peace; a Marine battalion commander who turned against the war; a man capable of waxing nostalgic about his days at Rand but also giving notice that he plans to soon release more classified documents about the nuclear threat.
The complexity of the man intrigued Ehrlich and Goldsmith, the documentary filmmakers who decided to resurrect Ellsberg's story for a new generation.
"This was a subject close to both of our hearts," said Ehrlich. "We focus on people driven by conscience to act at great personal risk. What could have more resonance than the story of Dan Ellsberg?"
Ehrlich's films have included Those Who Refused to Fight It, about Second World War conscientious objectors. Goldsmith's Everyday Heroes was about the domestic Peace Corps.
They began their quest to make the Ellsberg movie four years ago, raising money from a long list of contributors credited at the end of the film. Their interviews with key figures in Ellsberg's story includes a rare appearance by his co-defendant in the espionage case, Anthony Russo, who died shortly after telling his story on camera. The film is dedicated to him.
Ehrlich and Goldsmith raced to finish it in time for Academy Awards qualifications and wrapped it just two weeks ago, in time for the Toronto Film Festival and screenings in New York and Los Angeles.
Its future distribution plans are uncertain and fundraising continues. At a party after the Los Angeles premiere, one donor announced she would give $50,000 to keep the momentum going.
"To young people, it's a fresh story," said Goldsmith. "I would like them to see that it's possible to dissent and not be a traitor."
As for Ellsberg, who spent months copying the top-secret study on a Xerox machine, he now has his own website and is posting his opinions across the Internet in various forums. He notes that it took The New York Times three months to review the Pentagon Papers study and decide to publish it.
"If that had happened today," he said, "I would have posted it directly on the Internet."
Linda Deutsch covered the Pentagon Papers trial for The Associated Press.
-- The Associated Press