The Democratic Party is planning to hold an inquiry into whether President Donald Trump should be impeached over his contacts with Ukraine about the former vice-president, Joe Biden.
There were some calls for his impeachment during the years-long Russia inquiry, but this time House Speaker Nancy Pelosi has gone further and set up a group to look into it.
Legal scholars suggest presidents cannot be prosecuted while in office, so the only way he could be removed from the job would be by impeachment.
But just how does that happen? And exactly who has been impeached in the past? The answer may surprise you…
What is impeachment anyway?
In this context, to “impeach” means to bring charges in Congress which will form the basis for a trial.
The US constitution states a president “shall be removed from office on impeachment for, and conviction of, treason, bribery, or other high crimes or misdemeanours”.
The process of impeachment has to be started by the House of Representatives and only needs a simple majority to pass. The trial will be held in the Senate.
But here, a two-thirds vote is necessary for removal – and this milestone has never been reached in America’s history.
Who has actually been impeached?
Despite it being threatened on numerous occasions, only two presidents have ever actually been impeached.
Most recently, Bill Clinton – the 42nd president of the United States – found himself impeached on the grounds of perjury in front of a grand jury and obstruction of justice, after he lied about the nature of his affair with Monica Lewinsky and then allegedly asked her to lie about it as well.
The House voted 228 to 206 in favour of impeaching President Clinton for the first charge, and 221 to 212 on the second.
It should be noted that, at the time in December 1998, Mr Clinton’s approval rating as president was at 72%.
However, when the trial reached the Senate in 1999, it failed to get close to the two-thirds backing needed in order to pass. As an analysis piece the BBC ran at the time noted, “in their eagerness to bring down the president, they never stopped to think whether the charges could be proved beyond reasonable doubt”.
The second? Clue: It wasn’t Richard Nixon. (More on this lower down.)
In fact, the only other president impeached was Andrew Johnson, who served for four years from 1865 – the 17th person to hold the role.
He was impeached by the House in 1868. The vote came just 11 days after he got rid of Edwin Stanton, his secretary of war – a man who didn’t agree with his policies.
The parallels between Mr Stanton’s firing and that of FBI director James Comey – a man who disagreed with Mr Trump – did not go unnoticed in the American press.
Unlike Mr Clinton, however, Mr Johnson’s survival was a close call: the two-thirds majority was missed by just one vote, thanks to a number of Republicans.
Later, Iowa senator James Grimes explained: “I cannot agree to destroy the harmonious working of the Constitution for the sake of getting rid of an unacceptable president.”
Real Life. Real News. Real Voices
Help us tell more of the stories that matterBecome a founding member
So, could Mr Trump be impeached?
Analysis – Anthony Zurcher, BBC News, Washington
For months now, Democratic leaders in the House of Representatives have been playing a semantics game. They wanted those who supported and those who opposed a formal impeachment inquiry into President Donald Trump to both think they were getting what they wanted.
This strategy suggested a fear by Speaker Nancy Pelosi and others that heading down the path to impeachment would put moderate Democrats facing tough 2020 re-election fights at risk.
That calculus appears to have changed, after the rapid drumbeat of new revelations about Mr Trump’s contacts with Ukrainian President Volodymyr Zelensky. Now even middle-of-the road politicians are coming out in favour of impeachment proceedings.
The dam has broken. The genie is out of the bottle. Pick your metaphor. The simple fact is that Ms Pelosi – a keen judge of the political mood within her caucus – has made the decision to shift from resisting impeachment to -at the very least – being open to it.
The path forward is uncertain. The administration could back way from its across-the board stonewalling and give Congress some of the information it requests. Opinion surveys could show the latest drama is taking a toll on one party or the other, causing political will to crumble. Or, both sides could dig in for a long, gruelling battle that could drag into the darkest days of winter.
Say Trump IS impeached… would he be removed from office?
Republicans control the Senate, so Mr Trump would not be removed from office unless members of his own party turned on him.
The vast majority of Republicans have remained loyal to him.
Of course, there are the notable exceptions, such as Senator Mitt Romney who was a lone voice among Republican senators calling for more White House transparency over the Ukraine contacts.
But it looks like Mr Trump would remain in the White House, thanks to his support among Republicans.
In the wider public, the president remains unpopular but the appetite for impeachment is low.
A Monmouth University poll carried out this month – before the Ukraine story – suggests 35% of Americans feel Mr Trump should be impeached.
Finally – just how did Mr Nixon avoid impeachment?
He did what every sensible person does when they know the tide has turned against them. He quit.
Subscribe to the newsletter news
We hate SPAM and promise to keep your email address safe