The 47-volume history, consisting of approximately 3,000 pages of narrative and 4,000 pages of appended documents, took 18 months to complete. Ellsberg, who worked on the project, had been an enthusiastic early follower of the U.S. role in Indochina but, by the project’s end, had become seriously opposed to U.S. involvement. He felt compelled to reveal the nature of U.S. participation and leaked major portions of the papers to the press.

On June 13, 1971, The New York Times began publishing a series of articles based on the study, which was classified as “top secret” by the federal government. After the third daily installment appeared in the Times, the U.S. Department of Justice obtained in U.S. District Court a temporary restraining order against additional publication of the confidential material, challenging that further public distribution of the material would cause “immediate and irreparable harm” to U.S. national defense interests.

The Times, joined by The Washington Post, which also was in possession of the documents, fought the order through the courts for the next 15 days, during which time publication of the series was suspended. On June 30, 1971, in what is regarded as one of the most significant prior-restraint cases in history, the U.S. Supreme Court in a 6–3 decision freed the newspapers to resume publishing the material. The court held that the government had failed to give good reason for restraint of publication.