The Pentagon Papers
Even though there is risk involved when releasing classified information, the First Amendment typically trumps the Espionage Act. The Pentagon Papers case set the precedent.
According to the Encyclopedia Britannica, Secretary of Defense Robert McNamara commissioned the papers, and they were officially titled “Report of the Office of the Secretary of Defense Vietnam Task Force” (“Pentagon Papers” par. 1). In 1971, small portions of the Pentagon Papers were leaked to the media and distributed throughout the country. They revealed that the U.S. was intentionally expanding its role in the war, even after President Lyndon B. Johnson promised that he would not.
Lawsuits followed. Ultimately, the Supreme Court allowed the press to publish government secrets when The New York Times ran the truth about the Vietnam War (“Pentagon Papers” par. 4).

“Pentagon Papers.” Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web.