Ellsberg, who described Russo as his best friend at Rand, asked his colleague to brief him on the Viet Cong project. "I explained how the so-called enemy, the Viet Cong, and the North Vietnamese, were actually the legitimate parties and how the U.S. presence was illegal, immoral and unwise. I supplied him with reams of documentation," Russo later wrote in a personal account of the period. He was fired from Rand a short time later.

During one conversation with Ellsberg, he learned of a secret study commissioned by Defense Secretary Robert McNamara that chronicled the origins of the war. Ellsberg said that it showed that the U.S. had falsely charged North Vietnam with an act of unprovoked aggression in the Gulf of Tonkin, the basis for President Lyndon B. Johnson’s broadening of U.S. involvement in the war in 1964.

Russo said that when he heard about the fabrication of the Gulf of Tonkin incident, he urged Ellsberg to "turn that over to the newspapers."

Ellsberg was shocked by his friend’s subversive suggestion. "This was an extraordinary thing for someone who had until recently held a top-secret clearance to say to anyone, least of all to someone who still had a clearance," Ellsberg said Thursday in a statement distributed by the blog antiwar.com.

Russo’s and Ellsberg’s accounts differ on when the latter conversation occurred. Russo said it happened in late 1968; Ellsberg said that it was in September 1969, after he had read several volumes of the Pentagon Papers that had been stored at Rand. That was when he called Russo and asked for his help.

"I asked him if he knew where we could find a Xerox machine," Ellsberg said, "and within an hour he got back to me with the word that his then-girlfriend had a machine in her office we could use."

What followed were several weeks of furious copying behind locked doors of the girlfriend’s Hollywood advertising agency. The documents were given to New York Times reporter Neil Sheehan in March 1971. Publication of the first installments in June sparked an FBI manhunt for Ellsberg and an unprecedented attempt by the Nixon administration to restrain the newspaper from publishing any more of the information Ellsberg had provided.

Russo was harassed by police and placed under surveillance. When he was subpoenaed by a grand jury, he refused to testify against Ellsberg and was jailed for 45 days. A few days before Christmas 1971, both men were indicted on charges of conspiracy, theft and espionage.

Although Russo’s name was listed before Ellsberg’s in the court papers filed by the government, everyone called it the Ellsberg trial. This description only added insult to injury, as far as Russo was concerned. He believed that Ellsberg wanted to keep the limelight to himself and saw Russo as "horning in on his thing."

The co-defendants were quite unalike in many ways. Russo was large and rumpled, Ellsberg trim and elegant. Russo spoke in the rhetoric of a left-wing rebel, while Ellsberg, a former Marine, was far more measured.

Once the trial was underway, they clashed repeatedly on strategy. Russo wanted to radicalize the proceedings with defense witnesses such as activists Tom Hayden and Howard Zinn, but Ellsberg preferred more established figures, such as McGeorge Bundy and Theodore Sorensen, both of whom had worked in the Kennedy administration.

Perhaps none of it mattered. The case against them was dismissed May 11, 1973, after the court learned that a covert team had broken into the offices of Ellsberg’s psychiatrist looking for information to discredit the star defendant.

The break-in had been committed by operatives from the White House, whose crimes had come at the behest of Nixon and his top aides. Nixon resigned from office Aug. 9, 1974.

Russo, who worked for the Los Angeles County Probation Department after leaving Rand, returned to work for the county when the trial ended.

After his retirement and his mother’s death in the early 1990s, he moved back to Suffolk but continued as an activist for peace and other causes. He was married and divorced twice and had no children.

Lee Boek, a friend for more than 20 years, said Russo had a contrary streak and "never felt he got the credit he deserved" for his role in publicizing the Pentagon Papers.

He risked his life and his jobs. He suffered a lot for it," Boek said, adding that his friend saw himself as "a real patriot of this country, someone who fought for right and justice."

On Thursday, Ellsberg sought to give his former colleague and co-defendant his due.