In the Pentagon papers case, which safeguard did the US Supreme Court reaffirm?

In the Pentagon Papers case, the U.S. Supreme Court reaffirmed the principle of no prior restraint. This legal doctrine is grounded in the First Amendment's protections of free speech and press, indicating that the government cannot prohibit publication or restrict access to information before it is released. The case revolved around the Nixon administration's attempt to prevent the New York Times and the Washington Post from publishing classified documents concerning the Vietnam War.

The Supreme Court ruled that the government failed to meet the heavy burden necessary to justify prior restraint in this instance. By prioritizing freedom of the press and the public's right to know, the Court reinforced the idea that the government cannot impose prior restrictions on the media—even in matters of national security—unless it can demonstrate an immediate and grave threat that is almost certain to arise from publication.

The other options, such as habeas corpus, search warrants, and due process, are important legal concepts, but they are not central to the ruling in the Pentagon Papers case, which specifically addressed the issue of prior restraint on publication.