KENSINGTON, Calif. » Pentagon Papers leaker Daniel Ellsberg calls the revelations by a government contractor on U.S. secret surveillance programs the most "significant disclosure" in the nation’s history.

In 1971, Ellsberg passed the secret Defense Department study of U.S. involvement in Vietnam to The New York Times and other newspapers. The 7,000 pages showed that the U.S. government repeatedly misled the public about the war. Their leak set off a clash between the Nixon administration and the press and led to a landmark Supreme Court ruling on the First Amendment.

Ellsberg, 81, told The Associated Press Monday that the leaks by Edward Snowden, 29, to The Washington Post and The Guardian newspapers are more important than the Pentagon Papers as well as information given to the anti-secrecy website Wikileaks by Army Pfc. Bradley Manning, an intelligence analyst.

Snowden, a former CIA employee who later worked as a contractor for the National Security Agency, told the newspapers about a government program that tracks American phone records and another one that tracks phone and Internet messages around the world.

"I was overjoyed that finally an official with high or a former official with high access, good knowledge of the abusive system that he was revealing was ready to tell the truth at whatever cost to his own future safety, or his career, ready to give up his career, risk even prison to inform the American people," Ellsberg said.

"What he was looking at and what he told us about was the form of behavior, the practice of policy that’s blatantly unconstitutional. I respect his judgment of having withheld most of what he knows, as an information specialist, on the grounds that its secrecy is legitimate and that the benefit to the American people of knowing it would be outweighed by possible dangers. What he has chosen, on the other hand, to put out, again confirms very good judgment."

Manning is being tried in military court under federal espionage and computer fraud laws for releasing classified documents to WikiLeaks about the wars in Iraq and Afghanistan, among other items. The most serious charge against him is aiding the enemy.

Ellsberg recently expressed support for Manning but said he didn’t have access to information with the same "degree of significance" as the revelations released by Snowden.

"There has been no more significant disclosure in the history of our country. And I’ll include the Pentagon Papers in that," Ellsberg said of Snowden’s leak.

"I fear for our rights. I fear for our democracy, and I think others should too. And I don’t think, actually, that we are governed by people in Congress, the courts or the White House who have sufficient concern for the requirements of maintaining a democracy."