What is impeachment and how does it work?

Donald Trump faces impeachment for the second time after the deadly riots at the US Capitol building.

Speaker Nancy Pelosi said the House will proceed with legislation to impeach the President on Monday with just days remaining before he is due to leave office on January 20 when Joe Biden is inaugurated.

If the plans go ahead, it will be the first time in history that a US president has been impeached twice.

So how does impeachment work - and what could happen to Mr Trump?

What is impeachment?

As sitting presidents cannot be indicted, impeachment is a final check on the president's power.

It is a process where they are removed from their position - following a trial - and potentially barred from public office in future.

It can be used to remove presidents, vice presidents and senior civil officials such as judges who have gone rogue.

Plans to impeach Donald Trump for the second time come after the assault on the US Capitol by a number of his supporters. Credit: AP

What crimes can lead to impeachment?

Impeachment proceedings are a rare occurrence in the US - something of a last resort.

The US constitution states the president can be impeached and removed from office for "treason, bribery or other high crimes and misdemeanors".

This definition, and the behaviours that are deemed to have reached that threshold are therefore open to interpretation.

However, following Wednesday's unrest House leaders appear determined to act against Mr Trump despite the short timeline.

“It is absolutely essential that those who perpetrated the assault on our democracy be held accountable,” Ms Pelosi wrote.

“There must be a recognition that this desecration was instigated by the President.”

How does it work?

First, the House of Representatives - the lower chamber of Congress - must pass an Article of Impeachment by majority vote.

Once this passes, there is a trial in the Senate - the upper chamber of Congress - with the Chief Justice presiding in presidential cases.

The 100 senators are the jurors, they must decide whether the president is guilty of treason, bribery, or other high crimes or misdemeanours.

For the president to be removed from office there needs to be a 'super-majority' (two thirds) of Senators voting in favour.

Fifty-one members of the Senate are Republican.

President Clinton during his grand jury deposition in 1998. Credit: AP

Who's been impeached before?

Only two sitting presidents have actually had the Article of Impeachment passed in the House of Representatives.But no other US President has been impeached twice.

In 1868, Andrew Johnson was impeached after he illegally removed his Secretary of War, sending rising political tensions over boiling point.

The Senate needed 36 votes for guilty to get the super-majority. Johnson escaped by the skin of his teeth with 35 finding him guilty.

More recently, Bill Clinton was impeached in 1998 following the Monica Lewinsky scandal.

He faced two charges, one for perjury and one for obstruction of justice.

The super-majority requirement was 67 but he was acquitted, with the charges only getting 45 and 50 guilty votes respectively.

In fact, no president has ever been removed from office by the actual process of impeachment.

Richard Nixon faced an uphill battle against impeachment. Credit: AP

The one who probably came closest to that fate was Richard Nixon, who resigned in 1974 before impeachment proceedings could begin, and would have most likely removed him from office.

What action will be taken against Trump?

Ms Pelosi said that first the House will try to force vice president Mike Pence and the Cabinet to oust Mr Trump by invoking the 25th Amendment.

Ms Pelosi explained that the resolution calls on Mr Pence “to convene and mobilise the Cabinet to activate the 25th Amendment to declare the President incapable of executing the duties of his office”.

On Monday, House leaders will work to swiftly pass legislation to do that. If it is blocked by Republicans, which is likely, the House will convene for a full House vote on Tuesday.

The next step would be for the House to consider the articles of impeachment, Ms Pelosi said. The day for an impeachment vote has not been set.

The strategy would be to condemn the president’s actions swiftly but delay an impeachment trial in the Senate for 100 days to allow Mr Biden to focus on other priorities as soon as he is inaugurated on January 20.

Two Republican senators said they want Mr Trump to resign immediately rather than face impeachment.

Donald Trump's administration resumed executions in July. Credit: AP

What would impeachment mean for Donald Trump?

If successful, the resolution would remove Trump from office and Vice President Pence would “immediately exercise powers as acting President”, Ms Pelosi wrote.

Even though just a few days remain until the inauguration of President-elect Joe Biden, impeachment would bar President Trump from running for office ever again.

It would also strip him of his $200,000 per year pension and he would not get secret service security for the rest of his life.

Following the rioting, Mr Trump has committed to a “seamless transition of power” - but has said he will not attend Mr Biden's inauguration.

Why was Donald Trump impeached the first time?

The threat of impeachment has been a running theme throughout Mr Trump's presidency.

Action was initiated on December 18, 2019 when the House of Representatives approved articles of impeachment on charges of abuse of power and obstruction of Congress.

They point to Mr Trump pressuring Ukraine to investigate 2020 political rival Joe Biden while withholding as leverage military aid the country relies to counter Russia, as well as his efforts to block the House investigation.

Trump has called it "presidential harassment" and a "witch hunt".

Critics accused Trump of betraying the nation for his own political gain.

The Senate acquitted Trump of these charges on February 5, 2020.

Robert Mueller's investigation did not produce enough evidence that Donald Trump conspired with the Russian government. Credit: AP

What other investigations have taken place during Trump's presidency?

Earlier during his reign, Robert Mueller's investigation into links between the Trump campaign team and the Kremlin were investigated, but Mueller didn’t find enough evidence that the Trump campaign had conspired with the Russian government.

Former CIA director John O Brennan called Trump's performance during his summit with Russian president Vladimir Putin "nothing short of treasonous", saying it exceeded "the threshold of high crimes and misdemeanours".

Questions about Trump's presidency were also raised after the Stormy Daniels' accusations against him.

Sol Wisenberg, who conducted grand jury questioning of Bill Clinton during the Whitewater investigation, said: “The stuff on Stormy Daniels is not good for Trump.

Even a number of Republican politicians were astonished by Trump's summit with Putin Credit: AP

“I’m assuming he’s not going to be indicted because he’s a sitting president. But it leads him closer to ultimate impeachment proceedings, particularly if the Democrats take back the House.”

Trump’s former chief strategist Steve Bannon had previously warned Democrats could pursue impeachment proceedings if they won the midterm elections.

Trump’s former chief strategist Steve Bannon had previously warned Democrats could pursue impeachment proceedings if they won the midterm elections. Credit: PA

Yet again, Mr Trump faces all of the drama and the theatre of impeachment, will he survive that ultimate test set by the founders 232 years ago?