CNN  — 

The fateful moment when the House of Representatives on Wednesday impeaches President Donald Trump for a second time will rank among the defining moments of America’s story long after the citizens enduring these harrowing, tragic days are gone.

Fast-moving developments in the run-up to the vote have left Trump more politically vulnerable than he has ever been.

At least a handful of House Republicans plan to vote with Democrats to impeach.

In another startling sign that Trump’s incitement of a mob assault on Congress has shattered rigid political alignments right at the end of his term, Republican Senate Majority Leader Mitch McConnell has signaled he believes that impeachment will make it easier to rid the party of Trumpism.

By the end of the day, Trump will be saddled with a stain he will never be able to erase, as the first President to be impeached twice after his refusal to admit his election defeat shattered assumptions on the unassailability of stable government and the previously unbroken chain of peaceful US transfers of power. Save for the fracturing of the union before the Civil War, this country’s system of political checks and balances has never before been under the kind of strain imposed by an autocratic President desperate to cling to power.

A sense of unfolding history is magnified by growing evidence that America is fighting for democracy itself in a struggle that will endure after Trump leaves office next week at the latest. New warnings of violence by pro-Trump extremists in 50 states and militias on the march toward Washington are instigating the most oppressive sense since 9/11 that the homeland is under threat. But this time the danger to US freedom comes not from a foreign terrorist group but radicalized Americans.

The sole article of impeachment that the House is expected to pass Wednesday charging Trump with high crimes and misdemeanors is damning. Its simple clarity explains why this impeachment is no mere futile partisan ritual in the waning days of the most aberrant presidency in history.

“Donald John Trump, by such conduct, has demonstrated that he will remain a threat to national security, democracy, and the Constitution if allowed to remain in office, and has acted in a manner grossly incompatible with self-governance and the rule of law,” the article reads

It is an extraordinary mark of turbulent times and a lawless term that Trump will become the first president to be impeached twice – only 13 months after the House first resolved that his abuses of power merited removal from office.

In a poetic twist, the vote will take place in the very same chamber that lawmakers fled a week ago in fear of their lives from an invading mob seeking to harm Vice President Mike Pence and House Speaker Nancy Pelosi and to thwart the transfer of power to President-elect Joe Biden.

In time, the events of this disorienting week will take their place alongside milestones – including the Declaration of Independence, the abolition of slavery, Pearl Harbor and the assassination of President John Kennedy – that make up America’s sweeping narrative. But history is experienced in retrospect. Current events are lived forward in all their alarming intensity and are frightening because no one knows how they will end. And the country’s nerves were already at a breaking point nearly a year into a once-in-a-century pandemic that has brought death and sickness and further deepened stark political divides.

‘Armed combat’ in the Capitol

The formal impeachment vote in the House is far from the only barely believable twist leading up to Biden’s inauguration in seven days.

The horror of last week’s events and their grave implications are becoming even clearer as more details emerge about the day when a sitting President incited partisans to assault another branch of government in the act of finalizing his election defeat.

The idea that the rampage in which five people died was just a political outburst that got out of control was debunked Tuesday by the serious tone of a news conference held by the acting district attorney in Washington.

“I think people are going to be shocked with some of the egregious contact that happened within the Capitol,” Michael Sherwin said, referencing “mind-blowing” cases and charges including sedition and conspiracy. He said that some of those charged had military backgrounds.

One federal law enforcement official said the videos and other information viewed by investigators paint a scary picture of events inside the Capitol as police and federal agents battled to save lawmakers and staff.

“It was armed combat in that building,” the official said.

Some of the hardening of opinion among lawmakers against Trump may be attributed to briefings on those events and the pending threats to the inauguration.

After emerging from an all-senators briefing on inauguration security, Sen. Chris Van Hollen raised the specter of a “million militia march” on Washington.

“We have no idea how many will come. We need to be prepared,” the Maryland Democrat said.

A warning to the troops

In another unfathomable moment on Tuesday, America’s most senior military leaders warned there was no place for extremism in the ranks and that the troops must support and defend the Constitution. The statement was remarkable in itself. But that the Joint Chiefs decided it needed to be issued in the first place was one of the more frightening events of recent days.

In a simultaneous political earthquake, McConnell, who tethered his now-destroyed Republican majority to the bucking bronco of Trump’s presidency, made it known he was glad the President would be impeached.

McConnell’s unexpected move, first reported by The New York Times, came amid his disgust at the attack on the Capitol by Trump supporters and in the belief that another impeachment would help Republicans purge the stain of this presidency from the party.

McConnell didn’t say how he would vote in a Senate trial. But his shift keeps open the long-shot chance that sufficient Republicans could join a two-thirds majority to secure the first-ever conviction in a presidential impeachment.

In the House, Wyoming’s Rep. Liz Cheney, a staunch conservative, announced that she would vote for Trump’s impeachment, enshrining the split with her fellow members of the GOP House leadership.

“There has never been a greater betrayal by a President of the United States of his office and his oath to the Constitution,” Cheney said.

Two other Republicans, Reps. Adam Kinzinger of Illinois and John Katko of New York, also said they would vote to impeach, with a number of their GOP colleagues expected to follow suit in a vote that will echo through history, sources told CNN.

In another development that exacerbated the feeling of history unspooling at a breakneck pace, Pence wrote to the House to formally refuse to join the Cabinet in invoking the 25th Amendment to declare Trump no longer able to fulfill the duties of his office.

“I do not believe that such a course of action is in the best interest of our Nation or consistent with our Constitution,” Pence wrote, after Democratic leaders had warned that an intervention by the vice president would be the only step that could hold off Wednesday’s impeachment vote.

Trump delivers an ominous warning

Action inside the Capitol came as security forces poured into Washington to secure Biden’s inauguration and Trump noticeably dodged an opportunity to cool tensions.

While he said he never wants violence, the President used a trip to his border wall in Texas on Tuesday to reinforce the falsehoods and inflammatory language that ultimately led to his second impeachment.

He branded the process “a continuation of the greatest witch hunt in the history of politics” and warned it was “causing tremendous anger” and was “dangerous” for America at a “very tender time.”

In more ominous comments, Trump said talk of using the 25th Amendment to oust him from office bore no peril for him but could come back to haunt Biden.

“Be careful what you wish for,” the President warned.

Trump also defended his remarks last week at a rally close to the White House that ended with his crowd marching on the Capitol.

With only seven days left in office, the President’s mind is also turning again to a controversial raft of pardons that would constitute yet another abuse of power.

CNN’s Jamie Gangel, Pamela Brown and Kara Scannell reported Tuesday that the President is continuing to discuss pardons for himself and his adult children. One source said such a move was considered even more likely since last week’s events, although there was concern among some aides and allies about the public perception of pardons after the deaths of five people in the riot.

Such a move by the President would be seen in the United States and around the world as yet another insult to democracy. The historic damage that Trump has already inflicted upon America’s reputation in this regard is incalculable.

But the stakes surrounding Wednesday’s vote and what will be a prolonged struggle during the Biden administration to bolster US political institutions can be seen in remarks coming out of authoritarian Russia – the American adversary that interfered in the 2016 election in a bid to help Trump.

“Following the events that unfolded after the presidential elections, it is meaningless to refer to America as the example of democracy,” said Vyacheslav Volodin, the speaker of the lower house of the Russian Parliament and a supporter of President Vladimir Putin.

“We are on the verge of reevaluating the standards that are being promoted by the United States of America, that is exporting its vision of democracy and political systems around the world. Those in our country who love to cite their example as leading will also have to reconsider their views.”