What to know about impeachment amid effort to oust US defense secretary Pete Hegseth

What is impeachment?

The US constitution grants Congress authority to impeach and remove the president, vice-president and other federal “civil officers” for “Treason, Bribery, or other high Crimes and Misdemeanors”.

How does it work?

The first step in an impeachment process is in the House of Representatives, which considers articles of impeachment brought forward by a US representative against an eligible federal official. For the House to vote to impeach someone, it needs a simple majority to approve the articles of impeachment.

If the House votes to impeach someone, the matter is then presented to the US Senate, to which the constitution provides the power to try an impeachment and decide whether the official should be removed and barred from holding federal office in the future.

In the Senate, it would take a super-majority – two-thirds of the body – to convict and remove a person. If that occurs, the person is removed from office.

The Senate can also vote to dismiss the articles of impeachment, or create a committee to hear and consider evidence. A Republican aide told CNN last week that they believed that there is a “strong argument” for referring the matter to a committee for an investigation instead of going directly to trial.

According to the New York Times, impeachment resolutions – unlike legislation – do not expire or die at the end of a congressional session. Democrats, who won majorities in both the House and Senate in the US midterm elections, could also take up the matter when those majorities take effect, and they take control of the chambers, in January.

Does the process differ for the president and cabinet members?

The foundational steps are the same, requiring the same amount of votes in both the House and the Senate, with one crucial difference.

During an impeachment trial of a president in the Senate, the chief justice of the US presides over it. This provision makes sure that a vice-president, in their usual capacity as presiding officer of the Senate, does not preside over proceedings that could lead to their own elevation to the role of president.

During the impeachment trial of a cabinet member, however, the vice-president presides.

Who has been impeached before?

Three US presidents have been formally impeached by the House – Bill Clinton, Andrew Johnson and Donald Trump, who was impeached by the House twice during his first term. But they were all acquitted by the Senate. Richard Nixon faced articles of impeachment, but resigned prior to a full House vote.

No US president has ever been removed from office through impeachment.

If Hegseth is impeached, he would be the third cabinet secretary in US history to be impeached. The most recent was in 2024, when Joe Biden’s homeland security secretary, Alejandro Mayorkas, was impeached by House Republicans over his handling of immigration at the southern border. The Senate dismissed the charge without a trial.

No cabinet official has ever been removed from office through the impeachment process.