The U.S. House of Representatives has the power to impeach the president under the U.S. Constitution. Upon articles of impeachment, the U.S. Senate serves as the court with Congressional appointees from the U.S. House.
The House Judiciary Committee usually investigates and votes on impeachment charges before submitting them to the U.S. House for a full vote. Impeachment requires a majority vote to pass. Impeachment in the U.S. House of Representatives serves as part of the check and balances in government. As of 2014, the U.S. House has impeached only two presidents, President Andrew Johnson and President Bill Clinton. The practice is more common with federal judges.
If a simple majority agrees to impeach for even one article, the Senate takes over. They hold a trial with the President represented by his legal team and House members acting as prosecutors. The Chief Justice of the Supreme Court presides and the Senate is the jury. A guilty vote by two-thirds of the Senate results in a conviction, and the President is removed from office. A second vote determines by simple majority whether he can ever again hold public office.