The general principle which governs proceedings by mandamus is that whatever can be done without the use of that extraordinary writ, may not be done with it. It lies only when there is practically no other remedy.
The congressman was indicted in a federal district court for conspiring to accept bribes from aliens in exchange for introducing private bill in the House of Representatives to allow the aliens to remain in the country. The congressman filed a motion to dismiss the indictment on the grounds that it violated the Speech or Debate Clause of the Constitution, and the district court denied the motion. The congressman then petitioned the court of appeals for a writ of mandamus to direct the district court to dismiss the indictment. The court of appeals declined to issue the writ. The case was appealed on certiorari to the Supreme Court of the United States.
Should a court approve a writ of mandamus where direct appeal was an available remedy?
The Court affirmed the decision of the U.S. court of appeals. It explained that mandamus was appropriate only when the party seeking the writ had no other adequate means of attaining relief. In this instance mandamus was not appropriate because the congressman could have readily secured review of the district court's ruling by a direct appeal to the court of appeals.