The Pentagon Papers (officially named History of the U.S. Decision-Making Process on Viet Nam Policy) is the popularized name for a top-secret study conducted by the United States Department of Defense dealing with American involvement in Southeast Asia from World War II until 1967. Daniel Ellsberg, in 1971, was responsible for leaking this study to the New York Times, who subsequently began publishing sections of it on June 13, 1971. On June 29, Senator Mike Gravel entered the report into the public record of the Subcommittee on Public Buildings and Grounds.
The government obtained a federal court injunction to stop publishing the classified Pentagon Papers, which led to the Supreme Court case of New York Times Co. v. United States, against the New York Times and the Washington Post. The Court, with a 6-3 decision, ruled that the injunctions were unconstitutional because the government did not meet the "heavy burden of showing justification for the enforcement of such a prior restraint."
The government also charged Ellsberg with theft, espionage, and conspiracy. The charges were dropped due to members of President Richard Nixon's staff breaking into Ellberg's psychiatrist's office to obtain medical records.