United States President Donald Trump is hours away from being impeached for a second time as the House of Representatives debates whether to hold him responsible for the Jan 6 mob attack on the capitol building.

As the debate began, the US media reported that at least some Republicans in the House and Senate pointedly may support the impeachment articles.

The House convened around 9am (Eastern Time) and the lawmakers voted at 10:30am, approving the rules governing the impeachment article.

After passing the rules of procedure, the House is now proceeding to a two-hour debate. The final vote will begin between 3pm and 4pm.

'High crimes'

The impeachment article blames President Trump for “engaging in high crimes and misdemeanours by inciting violence against the Government of the United States.” To support the argument, the article cites Trump’s false claims of election fraud in the months leading up to the Jan 6 attack and a phone call to Georgia Secretary of State Brad Raffensperger, urging him to "find" votes to overturn the results there.

In pictures: Chaos, violence, mockery as pro-Trump mob occupies Congress

The impeachment article said that during an address to supporters on Wednesday, Trump "willfully made statements [that] encouraged — and foreseeably resulted in — lawless action at the Capitol, such as: 'if you don't fight like hell, you're not going to have a county anymore.'"

On Tuesday night, the House voted 223 to 205, asking Vice President Pence to invoke section four of the 25th Amendment to remove President Trump. Pence, however, has refused to do so.

At least 12 Republican lawmakers have said they would vote to impeach the president because he has betrayed his country and its constitution.

“There has never been a greater betrayal by a president of the United States of his office and his oath to the constitution,” said Congresswoman Liz Cheney, the No 3 Republican in the House and the daughter of former vice president Dick Cheney.

Preventive measures

Also on Tuesday, six House Republicans introduced a resolution to censure President Trump over his role in stoking last week’s violent riots, arguing that this was the best move as the impeachment would never get enough votes in the Senate to pass.

But after Pence’s announcement that he was not going to remove Trump, political observers in Washington see these as preventive moves, aimed at stopping Trump from making another irrational move like the crowd attack on the Congress building.

In a letter to House Speaker Nancy Pelosi just before the first vote, Pence wrote: “I do not believe that such a course of action is in the best interest of our Nation or consistent with our Constitution.”

He said the 25th amendment was "not a means of punishment or usurpation", and that invoking it would "set a terrible precedent".

Pence, who has been praised by both Republicans and Democrats for refusing to follow his boss’s advice to overturn the results of the 2020 presidential election, assured the nation that the Trump administration was committed to ensuring an orderly transition in its final days and that "now is the time to heal".

Pence has also promised to attend President-elect Joe Biden’s inauguration on Jan 20, unlike Trump who has opted out.

The resolution that urged Pence to get rid of Trump before the inauguration said the outgoing president "widely advertised and broadly encouraged" the protests that led to last week's violence. He also ignored calls to condemn his supporters' actions swiftly, it adds. It recalled that Trump repeatedly tried to delegitimise the presidential election results with false claims of widespread voter fraud.

Despite Pence’s refusal, the House moved forward with impeachment proceedings, making Trump the only US president to be impeached twice.

The move, however, has had little impact on Trump who said at a rally in Texas on Tuesday that "the 25th Amendment is of zero risk to me but will come back to haunt Joe Biden and the Biden administration."

Earlier on Tuesday, Trump said the impeachment move was ‘ridiculous’ and would “cause tremendous danger to our country and it's causing tremendous anger”.

Read: Trump claims impeachment causing ‘tremendous anger’

Encouraged by Pence’s refusal, House Republicans also lined behind their outgoing leader, and some defended his behaviour too, claiming that he never incited the crowd to attack the Capitol. They also argued that Congress had no role telling the vice president what to do.

“The vice president has given you your answer before you asked the question,” said Dan Bishop, Republican member of the House of Reps from North Carolina. “Your ultimatum does violence to a core feature of the architecture of the constitution.”

“Tomorrow, they are going to impeach a president who leaves in eight days, but they are going to impeach,” said Congressman Jim Jordan who has been awarded a presidential medal of freedom by Trump for his loyalty. “They are obsessed with him […] This is not about impeachment. This is about cancelling the president and all people who disagree with them.”