Final answer:
The First Amendment protects the freedom of the press, and the Supreme Court ruled that the government's desire to keep the papers classified did not justify violating the First Amendment.
Step-by-step explanation:
The Nixon administration's application for a court order to prevent the publication of the Pentagon Papers was a First Amendment issue because it involved the clash between freedom of the press and national security concerns.
The First Amendment protects the freedom of the press, which includes the right of newspapers to publish information without prior restraint from the government. The Supreme Court ruled in New York Times Co. v. United States that the government's desire to keep the Pentagon Papers classified was not strong enough to justify violating the First Amendment. The court allowed the publication of the papers, except for a few specific reasons such as revealing troop movements and naming undercover operatives.