Daniel Ellsberg grew up in Detroit and attended Cranbrook Kingswood School, then attended Harvard University, graduating with a Ph.D. in Economics in 1959 in which he described a paradox in decision theory now known as the Ellsberg paradox. He served as a company commander in the Marine Corps for two years, and then became an analyst at the RAND Corporation. A committed Cold War warrior, he served in the Pentagon in 1964 under Secretary of Defense Robert McNamara. He then served for two years in Vietnam as a civilian in the State Department, and became convinced that the Vietnam War was unwinnable. He further believed that nearly everyone in the Defense and State Departments knew, as he did, that the United States had no realistic chance of achieving victory in Vietnam, but that political considerations prevented them from saying so publicly. McNamara and others continued to state in press interviews that victory was "just around the corner". As the war continued to escalate, Ellsberg became deeply disillusioned.

The Pentagon Papers

Working again at Rand, Ellsberg managed to procure, photocopy, and return a large number of classified papers regarding the execution of the war. These documents later became collectively known as the Pentagon Papers. They revealed the knowledge, early on, that the war would not likely be won and that continuing the war would lead to many times more casualties than was admitted publicly. Further, the papers showed a deep cynicism towards the public and a disregard for the loss of life and injury suffered by soldiers and civilians.

Ellsberg knew that releasing these papers would most likely result in a conviction and sentence of many years in prison. Throughout 1970, Ellsberg covertly attempted to convince a few sympathetic Senators (among them J. William Fulbright) to release the Pentagon Papers on the Senate floor, because a Senator cannot be prosecuted for anything he says on record before the Senate. No Senator was willing to do so.

Finally, Ellsberg leaked the Pentagon Papers to The New York Times. On June 13, 1971, the Times began publishing the first installment of the 7,000 page document. For 15 days, NYT was prevented from publishing its articles on the orders of the Nixon administration. However, the Supreme Court soon ordered publication to resume freely. Although the Times did not reveal Ellsberg as their source, he knew that the FBI would soon determine that he was the source of the leak. Ellsberg went underground, living secretly among like-minded people. He was not caught by the FBI, even though they were under enormous pressure from the Nixon Administration to find him.

Fallout

The publication of the papers greatly detracted from public support for the war in Vietnam. This was a primary reason that President Nixon decided to make discrediting Ellsberg a high priority. Nixon's Oval Office tape from June 14 shows H. R. Haldeman describing the situation to Nixon.

To the ordinary guy, all this is a bunch of gobbledygook. But out of the gobbledygook comes a very clear thing: you can't trust the government; you can't believe what they say; and you can't rely on their judgment. And the implicit infallibility of presidents, which has been an accepted thing in America, is badly hurt by this, because it shows that people do things the president wants to do even though it's wrong, and the president can be wrong.
The release of these papers was politically embarrassing, not only to the incumbent Nixon Administration, but also to the previous Johnson and Kennedy Administrations. John Mitchell, Nixon's Attorney General almost immediately issued a telegram to the Times ordering that it halt publication. The Times refused, and the government brought suit against them.

Although the Times eventually won the trial before the Supreme Court, an appellate court ordered that the Times temporarily halt further publication. This was the first successful attempt by the federal government to restrain the publication of a newspaper; this was remarkable because prior restraint has historically been viewed as the most oppressive form of censorship. Ellsberg released the Pentagon Papers to other newspapers in rapid succession, making it clear to the government that they would have to obtain injunctions against every newspaper in the country to stop the story. The right of the press to publish the papers was upheld in New York Times Co. v. U.S..

Trial and Mistrial

On June 28, Ellsberg publicly surrendered to the US Attorney's Office in Boston, Massachusetts. He was taken into custody believing he would spend the rest of his life in prison; he was charged with theft, conspiracy, and espionage.

In one of Nixon's actions against Ellsberg, G. Gordon Liddy and E. Howard Hunt broke into Ellsberg's psychiatrist's office in September 1971, hoping to find information they could use to discredit him. The revelation of the break-in became part of the Watergate scandal. According to Ellsberg's autobiography, on May 3, 1972 the White House secretly flew a dozen Cuban CIA "assets" to Washington DC with orders to "totally incapacitate" him. (They backed out because the crowd was too large.) Because of the gross governmental misconduct, all charges against Ellsberg were eventually dropped.

Later life

Daniel Ellsberg has continued as a political activist, giving lecture tours and speaking out about current events. Recently he garnered criticism from the George W. Bush administration for praising Katharine Gun and calling on others to leak any papers that reveal deception regarding the 2003 invasion of Iraq. Ellsberg currently serves as a senior research associate at the Massachusetts Institute of Technology's Center for International Studies.

Daniel Ellsberg also testified in 2004 at the conscientious objector hearing of Camilo Mejia at Fort Sill, Oklahoma.

The Pentagon Papers is a 2003 movie documenting Ellsberg's life starting with his work for Rand Corp and ending with the day on which the judge declared his treason trial a mistrial.

Ellsberg was arrested in November 2005 for protesting against George W. Bush's conduct of the War in Iraq.