On this day in 1974, the Supreme Court decided United States v. Nixon, a ruling that played a key role in President Richard Nixon’s resignation from office.

The justices issued their decision just sixteen days after hearing oral arguments in the case. The President, they held, could not cite executive privilege as a reason for refusing to release tape recordings that had been subpoenaed in a criminal case related to the Watergate scandal.

Warren Burger, the man Nixon had appointed as Chief Justice, delivered the unanimous Opinion of the Court. (Justice William Rehnquist, who had worked in the Nixon Administration, recused himself in the case.)

“For seventeen minutes he calmly expounded what seemed at times like a patient lesson in American history and government,” wrote Anthony Lewis, the Supreme Court reporter for the New York Times. “All was measured, professional, stately. It was the law, offering us once again that reassurance of constitutional order that we require of it in this turbulent country.”

Although Burger never mentioned the impeachment proceedings against the President, the Court’s decision “adds to the feeling that the last act of Richard Nixon’s drama is at hand,” Lewis noted. “In the White House there is visibly taking hold the shattering realization that this President is going to be impeached.”

The legal events that led to this dramatic moment at the Supreme Court began on March 1, 1974, when, in the course of an investigation initiated by a Special Prosecutor, a grand jury indicted former U.S. Attorney General John Mitchell and six others, all of whom were either on the White House staff or Nixon’s reelection committee. They were charged with obstruction of justice and conspiracy to defraud the country, among other offenses. In April, the prosecutor issued a subpoena to Nixon, whom the grand jury named an unindicted co-conspirator, requesting that he produce tapes, papers, transcripts, and memoranda. Nixon’s lawyer motioned to quash the subpoena, claiming executive privilege immunized the president against such requests. The District Court denied the motion, and the President appealed the decision.

The justices worked together through several drafts to produce an opinion they could all sign on to. According to Bob Woodward and Scott Armstrong’s inside account of the Burger Court, The Brethren, Justice Potter Stewart told his law clerks that a law school professor would have given Burger’s first draft a “D”;  he and other justices had improved it to a “B.”

The heart of the Court’s decision was the rejection of Nixon’s argument that he could not be legally compelled to produce records of “confidential conversations between a President and his close advisors” because to do so “would be inconsistent with the public interest.” The judiciary lacked the authority to reviews a presidential claim of executive privilege, Nixon argued, because to do so would violate the constitutional principle of separation of powers.

The Court rejected this sweeping assertion of executive privilege, noting that separation of powers principles do not prevent the Court from routinely reviewing the acts of the other branches of the federal government. As support for this point, the Court cited Marbury v. Madison’s famous proclamation that “it is emphatically the province and duty of the judicial department to say what the law is.”

To Nixon’s argument that communications between high government officials and their advisers must be protected so that those officials and advisers won’t feel the need to “temper candor,” the Court explained that absent a need to protect military, diplomatic, or national security secrets, the duty of the courts outweighs the interest in confidentiality of Presidential communications.

Sixteen days after the Court’s ruling, Nixon resigned.