Daniel Ellsberg is an American former military analyst best known for leaking the Pentagon Papers in 1971. These classified documents revealed the U.S. government's secret involvement in the Vietnam War, showing that officials had misled the public about the war's progress and intentions. His actions sparked a national debate about government transparency and the public's right to know. Ellsberg's leak led to a landmark Supreme Court case, New York Times Co. v. United States, which upheld the newspaper's right to publish the documents. He became a symbol of whistleblowing and civil disobedience, advocating for peace and accountability in government actions.