"Crazy Nancy Pelosi's House Democrats have branded themselves with an eternal mark of shame," Mr Trump told the crowd in battleground Michigan, where he took the stage just minutes before becoming only the third president in US history to be impeached. "It's a disgrace."

It was a dramatic and discordant split-screen moment, with Mr Trump emerging from a mock fireplace like Santa Claus at the Christmas-themed rally as the impeachment debate in Washington played out. It was also Mr Trump's longest rally ever, according to the tracking site Factbase, clocking in at two hours and one minute.

Donald Trump congratulated Boris Johnson on election win in phone call

The first charges him with abuse of power for allegedly pressuring the president of Ukraine to investigate his Democratic rivals while crucial US security aid was being withheld. The second charges him with obstruction of Congress for stonewalling investigative efforts.

Yet there is little chance Mr Trump will be convicted by the Republican-controlled Senate and removed from office - a fact the president and his allies have pointed to as they have tried to minimise the votes' significance.

Still, Mr Trump clearly was stung by the stain that an "ugly" impeachment will attach to his legacy.

"After three years of sinister witch hunts, hoaxes, scams, tonight the House Democrats are trying to nullify the ballots of tens of millions of patriotic Americans," Mr Trump said, claiming that it was the Democrats who were "interfering in America's elections" and "subverting American democracy."

Mid-rally, an aide held up a sign notifying Mr Trump of the impeachment vote count and the president announced to the crowd that "every single Republican voted for us. Whoa. Wow, wow. ... and three Democrats voted for us".

During the rally, Mr Trump went after several legislators by name, including Democratic Republican Debbie Dingell of Michigan, whose husband, former Republican John Dingell, died earlier this year.

Mr Trump said Debbie Dingell had thanked him for "A-plus treatment" after her husband's death, telling the president that if her husband were looking down he would be thrilled.

"I said 'that's OK. Don't worry about it','" Mr Trump told the crowd. "Maybe he's looking up. I don't know." Some in the crowd gasped.

Ms Dingell responded by tweet, saying Mr Trump's "hurtful words just made my healing much harder."

Mr Trump spent much of his marathon speech zigzagging between impeachment and unrelated topics, punctuating his remarks with more profanity than usual. He offered an extended riff on US pilots being more attractive than"Top Gun" star Tom Cruise, went after Democratic presidential candidate Pete Buttigieg's difficult-to-pronounce last name and revelled - yet again - in his 2016 victory.

And after a day of harsh tweets, Mr Trump at times projected a less-concerned attitude toward what he called "impeachment lite".

"It doesn't really feel like we're being impeached," he said shortly after taking the Christmas tree-adorned stage. Later, he added: "I don't know about you, but I'm having a good time. It's crazy."

At another point, he declared: "I'm not worried. I'm not worried."

Mr Trump also worked to highlight the Republicans who have stood with him, telling the crowd that the Republican Party has "never been so united" and predicting victory in 2020.

Aides had said Mr Trump would wait until the House had finished voting before speaking at the rally, but he appearing onstage ahead of the votes and promoted "the best speech you've ever heard".

Throughout the day, Mr Trump had stared down the impending vote as he has every obstacle in his presidency: by broadcasting his grievances via tweet.

"Can you believe that I will be impeached today by the Radical Left, Do Nothing Democrats, AND I DID NOTHING WRONG!" Mr Trump wrote in one of 45 tweets posted before noon. He asked his followers to "Say a PRAYER!"

Mr Trump's urgency appeared to escalate later in the day as he switched to all capital letters: "SUCH ATROCIOUS LIES BY THE RADICAL LEFT, DO NOTHING DEMOCRATS. THIS IS AN ASSAULT ON AMERICA, AND AN ASSAULT ON THE REPUBLICAN PARTY!!!!"

As the impeachment debate wore on, Trump aides, including White House counsellor Kellyanne Conway, fanned out across Capitol Hill to bolster the president's message that impeachment is helping Republicans and damaging Democrats. Vice-president Mike Pence got to Michigan ahead of Trump for a daylong bus tour before the Battle Creek rally.

Serving as a warm-up act at the rally, Mr Pence labelled the impeachment drive "a disgrace" and told the crowd that Democrats were "trying to impeach this president because they know they can't defeat this president."

Ms Pelosi and the Democrats were "having their say tonight," he said, "but the Republican Senate is going to have their say in January".

Mr Trump's campaign has experienced a surge in contributions and volunteers during the impeachment inquiry and aides were hoping to raise an additional $2 million Wednesday ahead of the votes.

'It's a disgrace': Donald Trump reacts to becoming the third US president to be impeached