Section 4 - The Text
The President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors
Section 4 - The Meaning
The Constitution provides that the president, vice president, and other federal officers can be removed from office upon impeachment by the House and conviction by the Senate of treason, bribery, or other serious crimes. The process was begun only three times in U.S. history against a president — against Andrew Johnson, Richard Nixon (although he resigned before Congress could formally act) and Bill Clinton.
The impeachment process begins in the House of Representatives with a vote to impeach. Then the president (or other accused government official) stands trial for the accusations in the Senate. The Chief Justice of the United States presides at an impeachment trial of the president.
In all impeachment trials, members of the House serve as prosecutors and the full Senate sits as the jury. The accused official must be convicted by a two-thirds vote of the Senate to be removed from office.