Impeachment became a household word in America during the process in the late 1990's which may have removed President Clinton from office. Ultimately impeachment was not taken to its final conclusion with regards to President Clinton - but the mere initiation of the process was enough to cause President Clinton huge international embarrassment. It is also an aspect of horizontal federalism that the "world's most powerful man" can be brought before Congress to account for his actions and to be punished by Congress.
What is impeachment?
It is the process of removing senior public servants from office, and takes the form of a trial.
Who can impeach the president?
The 435 members of the lower house of Congress, the House of Representatives, can decide whether he/she can be charged with impeachable offences, and the 100 members of the upper house, the Senate, must decide whether he/she is guilty. His/her sentence would be removal from office.
What is an impeachable offence?
The US Constitution states that a president, vice-president, senior civil servants and judges can be removed if found guilty of "treason, bribery or other high crimes and misdemeanours" which are not defined.
President Clinton's alleged crime - lying on oath - was investigated by what was known as the Starr Commission. Once Starr had done his work, he presented his report to Congress.
The report was studied by 2 lawyers working for the House judiciary committee - one represented the Democrats and the other represented the Republicans. There were 36 people on this committee; 21 Republicans and 15 Democrats. The committee met and decided whether to vote for "articles of impeachment". The whole House then had to decide whether to agree with the articles. A simple majority in the House transfered the whole process to the Senate where a senior judge presided over the hearing and all 100 Senators acted as jurors. A two-third majority in the Senate would have secured the conviction of President Clinton. This did not happen.
Has a president ever been impeached before?
No. Andrew Johnson faced impeachment proceedings in 1868 but was cleared by the Senate. Richard Nixon resigned in 1974 before full proceedings began. In Clinton's case, the Senate voted not to proceed with impeachment - in many senses, the damage to the integrity of the president had already been done and his removal may simply have left America in a political vacuum especially as the whole process could have taken some months from start to finish.