In the 1993 case, Judge Walter L. Nixon Jr., a former chief judge for the Southern District of Mississippi, challenged his removal by the Senate after he was convicted of perjury, sent to prison and impeached by the House.

Judge Nixon said he had not received the trial guaranteed by the Constitution because a committee of senators, rather than the whole Senate, had heard the evidence against him. The full Senate went on to vote to remove him by far more than the constitutionally required two-thirds majority.

The Supreme Court unanimously ruled against Judge Nixon. Chief Justice Rehnquist said the matter was a “political question,” meaning that it was for the Senate to decide how to conduct its impeachment trials.

Chief Justice Rehnquist used his opinion in the case to reflect on presidential impeachments, though he could not have known he would preside over the trial of the second one in the nation’s history. There were particularly good reasons for the Supreme Court to stay out of the impeachment process, Chief Justice Rehnquist wrote, “if the president were impeached.”

“The legitimacy of any successor, and hence his effectiveness, would be impaired severely, not merely while the judicial process was running its course, but during any retrial that a differently constituted Senate might conduct if its first judgment of conviction were invalidated,” he wrote.