As the House prepares for impeachment, President Donald Trump faces a single charge — “incitement of insurrection” — over the deadly riot at the US Capitol, according to a draft of the articles obtained by The Associated Press.

Lawmakers are set to introduce the legislation on Monday, with voting mid-week. Pelosi’s leadership team will also seek a quick vote on a resolution calling on Vice President Mike Pence and Cabinet officials to invoke the 25th Amendment.

The four-page impeachment bill draws from Trump’s own false statements about his election defeat to Democrat Joe Biden; his pressure on state officials in Georgia to “find” him more votes; and his White House rally ahead of the Capitol siege, in which he encouraged thousands of supporters to “fight like hell” before they stormed the building on Wednesday.

A violent and largely white mob of Trump supporters overpowered police, broke through security lines and windows and rampaged through the Capitol, forcing lawmakers to scatter as they were finalising Biden’s victory over Trump in the Electoral College.

“President Trump gravely endangered the security of the United States and its institutions of Government,” the legislation said.

The bill from Reps David Cicilline of Rhode Island, Ted Lieu of California, Jamie Raskin of Maryland and Jerrold Nadler of New York, said Trump threatened “the integrity of the democratic system, interfered with the peaceful transition of power” and “betrayed” trust.

“He will remain a threat to national security, democracy, and the Constitution if allowed to remain in office,” they wrote.

Rep Adam Schiff, D-Ca, told CBS on Monday, “We need to move forward with alacrity.”

House Speaker Nancy Pelosi says the House will proceed with legislation to impeach Trump as she pushes the vice president and the Cabinet to invoke constitutional authority to force him out, warning that Trump is a threat to democracy after the deadly assault on the Capitol.

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

A Republican senator, Pat Toomey of Pennsylvania, joined Republican Sen Lisa Murkowski of Alaska over the weekend in calling for Trump to “resign and go away as soon as possible.”

Matter of urgency

Lawmakers warned of the damage the president could still do before Joe Biden is inaugurated Jan 20. Trump, holed up at the White House, was increasingly isolated after a mob rioted in the Capitol in support of his false claims of election fraud. Judges across the country, including some nominated by Trump, repeatedly dismissed cases and Attorney General William Barr, a Trump ally, said there was no sign of any widespread fraud.

“We will act with urgency, because this President represents an imminent threat,” Pelosi said in a letter late Sunday to colleagues emphasising the need for quick action.

“The horror of the ongoing assault on our democracy perpetrated by this President is intensified and so is the immediate need for action.”

During an interview on “60 Minutes” aired on Sunday, Pelosi invoked the Watergate era when Republicans in the Senate told President Richard Nixon, “It’s over.”

“That’s what has to happen now,” she said.

Pence has given no indication he would act on the 25th Amendment. If he does not, the House would move toward impeachment.

Toomey said he doubted impeachment could be done before Biden is inaugurated, even though a growing number of lawmakers say that step is necessary to ensure Trump can never hold elected office again.

“I think the president has disqualified himself from ever, certainly, serving in office again,” Toomey said. “I don’t think he is electable in any way.”

Murkowski, long exasperated with the president, told the Anchorage Daily News on Friday that Trump simply “needs to get out.” A third, Sen Roy Blunt, R-Mo, did not go that far, but on Sunday he warned Trump to be “very careful” in his final days in office.

On impeachment, House Democrats would likely delay for 100 days, sending articles of impeachment to the Senate for trial, to allow Biden to focus on other priorities.

Sen Marco Rubio, R-Fla, said that instead of coming together, Democrats want to “talk about ridiculous things like ‘Let’s impeach a president’” with just days left in office.

Still, some Republicans might be supportive.

Nebraska Sen Ben Sasse said he would take a look at any articles that the House sent over. Illinois Rep Adam Kinzinger, a frequent Trump critic, said he would “vote the right way” if the matter were put in front of him.

The Democratic effort to stamp Trump’s presidential record — for the second time — with the indelible mark of impeachment advanced rapidly after the riot.

Rep. David Cicilline, D-R.I, a leader of the House effort to draft impeachment articles accusing Trump of inciting insurrection, said Sunday that his group had 200-plus co-sponsors.

Potentially complicating Pelosi’s decision about impeachment was what it meant for Biden and the beginning of his presidency. While reiterating that he had long viewed Trump as unfit for office, Biden on Friday sidestepped a question about impeachment, saying what Congress did “is for them to decide.”