The Pentagon Papers refer to a classified government report that detailed the United States' political and military involvement in Vietnam from 1945 to 1967. The documents revealed that the government had misled the public and Congress about the scope and nature of the U.S. role in the Vietnam War. In 1971, former military analyst Daniel Ellsberg leaked the Pentagon Papers to the press, leading to a significant legal battle over freedom of the press. The publication of these documents sparked widespread public outcry and contributed to growing anti-war sentiment in the United States.