The majority opinion, by Chief Justice William Rehnquist, held that the courts may not review the impeachment and trial of a federal officer because the Constitution reserves that function to a coordinate political branch.

Furthermore, because the word try was originally understood to include factfinding committees, there was a textually demonstrable commitment to give broad discretion to the Senate in impeachments.

The Court further ruled that involving the judiciary would prevent finality without clear remedy and bias post-impeachment criminal or civil prosecutions, which the Constitution explicitly allows.

Justices Byron White, Harry Blackmun, and David Souter concurred, but voiced concern that the Court was foreclosing the area for review.

In Powell, a grant of discretionary power to Congress was deemed to be justiciable because it required a mere "interpretation" of the Constitution.