Offenses that could prompt impeachment are treason, bribery or "other high crimes and misdemeanors."
The inclusion of "other high crimes and misdemeanors" gives the legislative branch flexibility to investigate an array of allegations.
One article of impeachment is drafted for each alleged offense.
In the House, if a simple majority votes in favor of impeachment, the chief justice of the Supreme Court
presides over a trial in the Senate. A two-thirds majority is required to convict and remove a president from office.
The Founding Fathers modeled the impeachment clause after a system in Britain which gives Parliament the authority to investigate royal advisers and other higher officials.
Countries around the globe have different processes for ousting a leader, often involving courts and/or legislative bodies.
US impeachment trials:
Congress has conducted two presidential impeachment trials: President Andrew Johnson in 1868, for firing a cabinet secretary without the consent of Congress, and President Bill Clinton
in 1998 for perjury and obstruction of justice.
Both Johnson and Clinton were acquitted, so they stayed in office.
President Richard M. Nixon
faced possible impeachment on the grounds of obstruction of justice, abuse of power and contempt of Congress in relation to the Watergate scandal.
He resigned in 1974, before a vote was conducted in the House of Representatives.
In addition to the presidential impeachments, Congress has carried out 17 other trials for federal officials including judges, a cabinet member and a senator.
On the state level, state legislatures have the power to impeach and remove governors. Two notable examples are Arizona Governor Evan Mecham in 1988
and Illinois Governor Rod Blagojevich
President Andrew Johnson (1865-1869)
Andrew Johnson, a Democrat, took office after the assassination of President Abraham Lincoln in 1865. Amid efforts to unite the country after the Civil War,
Johnson clashed with the "Radical Republicans" who wanted to accelerate the process of Reconstruction and grant rights to free slaves. To introduce a check on his power,
Congress passed a law barring the president from firing appointed officials, including cabinet secretaries, without Senate approval.
February 21, 1868 - Johnson dismisses Secretary of War Edwin Stanton, who backed the "Radical Republicans" campaign for Reconstruction.
March 5-May 26, 1868 - Trial in the Senate. Johnson is acquitted with a vote of 35-19, one vote shy of the two thirds majority needed to remove the president. Johnson serves out the rest of his term (until March 4, 1869), but he doesn't run for re-election. Democrats opt to nominate Horatio Seymour over Johnson during the prelude to the 1868 election.
1926 - The Supreme Court strikes down the Tenure of Office Act, the basis for Johnson's impeachment.
President Bill Clinton (1993-2001)
Clinton was sued in 1994 by Paula Jones for sexual harassment. Although Clinton and Jones eventually settled the suit rather than going to trial, the litigation sparked an investigation into whether Clinton obstructed justice and lied under oath. The probe centered on Clinton's relationship with a White House intern, Monica Lewinsky.
The president repeatedly denied that they had had an affair but eventually said that their relationship was inappropriate. The Clinton investigation was overseen by a special prosecutor, Kenneth Starr, who was originally appointed to look into possible financial crimes involving an Arkansas land deal and a development firm called Whitewater. In 1998, after a four-year investigation, Starr produced a 445-page report detailing Clinton's relationship with Lewinsky. The report listed acts that could be grounds for impeachment.
December 19, 1998 - Four articles of impeachment are set forth in the House of Representatives
. Two articles are approved. One, approved by a 228-206 vote, alleges that Clinton committed perjury when he told a grand jury that he did not have an affair with Lewinsky.
The other, approved by a 221-212 vote, alleges that Clinton coerced Lewinsky to lie under oath about their relationship. Two other articles, alleging abuse of power and further perjury, fail to garner a simple majority.
Failed measures to impeach American presidents:
While presidential impeachments are rare in the United States, it is not unusual for members of Congress to introduce resolutions seeking to oust the commander in chief. Every president since Ronald Reagan has been threatened with impeachment by members of the House.
President Ronald Reagan (1981-1989) -
Two separate measures were introduced to impeach Reagan
. The first, in 1983, was for offenses related to the invasion of Grenada. The second, in 1987, was tied to the Iran-Contra Affair.
President Barack Obama (2009-2017) -
In anticipation of potential military campaign in Syria in after the regime allegedly used chemical weapons in 2013,
Rep. Walter Jones (R-NC) prepared a resolution to impeach Obama
for going to war without consent from Congress.
President Donald J. Trump (2017-present) -July 12, 2017 -
A resolution to impeach Trump for obstruction of justice in relation to the Russian election-meddling probe
October 11, 2017 -
Rep. Al Green presents articles of impeachment against Trump, but does not force a vote. On December 6, the House votes to table the resolution
Notable world leaders impeached 2015-present:
Brazil - Dilma Rousseff
Amid a severe recession, Rousseff was accused of hiding a budget deficit to secure her re-election. The tumult was intensified by allegations of widespread corruption within the Brazilian government, although Rousseff herself was not linked to bribery and other schemes.
May 12, 2016 - The Senate votes 55-22 to start an impeachment trial.
Rousseff says she is the victim of a "great injustice."
Guatemala - Otto Pérez Molina A United Nations investigation into the Otto Pérez Molina administration
uncovered evidence that the president and his aides took bribes in exchange for tax breaks for companies and individuals seeking to import goods into Guatemala.
September 2, 2015 - The attorney general issues an arrest warrant for Pérez Molina.
June 17, 2016 - In a separate case, Pérez Molina is charged with embezzlement and money laundering.
South Korea- Park Geun-hye
Park Geun-hye's legal problems grew out of her close relationship with Choi Soon-sil, a church leader and spiritual mentor who allegedly encouraged her to pressure companies into making large donations to foundations affiliated with the church. Park is the first South Korean president to be impeached. Three weeks after she was removed from office, Park was arrested and charged with multiple criminal offenses.
March 10, 2017 - Park is removed from office.
The decision leads to demonstrations, as Park's supporters protest her removal from office while opposition groups cheer the court's opinion. The conviction strips her of the immunity granted to presidents in South Korea, clearing the way for criminal charges.