All the counts involved Chase's work as a trial judge in lower circuit courts. (In that era, Supreme Court justices had the added duty of serving as individuals on circuit courts, a practice that was ended in the late 19th century.) The heart of the allegations was that political bias had led Chase to treat defendants and their counsel in a blatantly unfair manner. Chase's defense lawyers called the prosecution a political effort by his Democratic-Republican enemies. In answer to the articles of impeachment, Chase argued that all of his actions had been motivated by adherence to precedent, judicial duty to restrain advocates from improper statements of law, and considerations of judicial efficiency.
The Senate voted to acquit Chase of all charges on March 1, 1805, and he returned to his duties on the court. He is the only U.S. Supreme Court justice to have been impeached.[3]
The acquittal of Chase -- by lopsided margins on several of the counts -- is believed to have helped ensure that an independent federal judiciary would survive partisan challenge. As Chief Justice William Rehnquist noted in his book, Grand Inquests, some people expressed opinions at the time of Chase's trial that the Senate had absolute latitude in convicting a jurist it found unfit, but the acquittal set an unofficial precedent that judges would not be impeached based on their performance on the bench. All judges impeached since Chase have been accused of outright criminality.
