Supreme Court justices serve for life, unless they resign, die or are impeached and removed from office. The reason for their lifetime tenure is to enable them to make decisions free from any pressure by the executive or legislative branches of government. Since the Supreme Court first convened in 1790, there have been 112 justices and only one ever has been impeached.
In 1804, the U.S. House of Representatives voted to impeach Associate Justice Samuel Chase. A signer of the Declaration of Independence, Chase was appointed to the U.S. Supreme Court by President George Washington in 1796. A Federalist, Chase irked Thomas Jefferson and his Republican allies in Congress, and was impeached on politically motivated charges of acting in a partisan manner during several trials. However, in 1805 Chase was acquitted by the Senate, a decision that helped safeguard the independence of the judiciary. He served on the court until his death in 1811.
In 1969, Abe Fortas became the first—and, to date, only—Supreme Court justice to resign under the threat of impeachment. Named to the court by President Lyndon Johnson in 1965, Fortas was forced to step down due to financial improprieties that involved him agreeing to act as a paid consultant to the family foundation of a man under investigation for securities fraud.
In addition to Samuel Chase, 14 other federal judges (who are appointed by the president and confirmed by the Senate) have been impeached over the course of American history, on charges ranging from drunkenness on the bench to accepting bribes. The first impeachment was in 1803 and the most recent was in 2010. Eight of the jurists were convicted by the Senate and removed from office, while three were acquitted and three resigned.