The House of Representatives Democratic Majority announces the beginning of the impeachment investigation formally starting a process with no firm timetable.
House committees investigate allegations of wrongdoing by the president, hearing from witnesses and gathering evidence. Their conclusions are sent in a report to the Judiciary Committee.
Judiciary Committee decides whether the reports contain evidence of wrongdoing, and if so, drafts articles of impeachment. The committee then votes on whether to send to the House.
The House debates the articles of impeachment and votes. If a majority of the members approve any of the articles, the president is formally impeached, but remains in office, pending the outcome of the Senate trial.
Impeachment does not require the president to be found guilty of breaking the law. The Constitution says impeachable offenses include "treason, bribery or other high crimes and misdemeanors," but with no specific definitions, it's up to Congress to arbitrate.
The Senate conducts a trial using the articles of impeachment. The Chief Justice of the United States serves as judge. The senators serve as jury. House members serve as prosecutors. And the president's lawyers serve as his defense.
After considering the evidence, the Senate votes on the articles, with two-thirds of sitting members needed to convict. A conviction removes the president from office.
If removed, the president is replaced in office by the vice president. There is no appeal process.