"This was an election that we won easily. We won it by a lot," Trump said to the lawmakers and Republican supporters in the ballroom of a Gettysburg hotel. "Very sad to say it -- this election was rigged and we can't let that happen. We can't let it happen for our country. This election has to be turned around."
His claims have been widely debunked by elections officials from both parties and in a series of court challenges that ended in defeat for the Trump campaign. Democrat Joe Biden won the 2020 election by more than 6 million votes, and by the identical Electoral College margin that Trump amassed in 2016.
Trump's comments came near the conclusion of a lengthy presentation by his personal attorney, Rudy Giuliani, who introduced a series of witnesses – some in person and some over video conference – who shared stories of what they believed were election oddities and irregularities.
A spokesperson for Secretary of State Kathy Boockvar called the claims "tired conspiracy theories" that have been "debunked and dismissed by the courts."
"Continuing to repeat these falsehoods in front of the cameras only harms the democracy that so many Americans have died to protect," the spokeswoman said.
The Biden campaign declined to respond to the president's comments, referring reporters to an earlier statement that called Trump's reaction "a sideshow."
"Look, the election is over, virtually everyone on Earth has accepted that truth except for Donald Trump and Rudy Giuliani, the Trump campaign has been laughed out of every courtroom, with their meritless and baseless lawsuits meant to undermine the will of the American people," spokeswoman Kate Bedingfield said.
Trump had considered flying to Gettysburg to appear at the GOP event in person, but shortly before the meeting was scheduled to begin, reporters were told there would be no trip. At one point after the meeting was underway, Trump could be overheard on a speaker phone held by another of his lawyers, Jenna Ellis, providing direction to Giuliani.
When he addressed the group by phone, Trump said the anecdotes presented at the caucus meeting represent only a small fraction of the sworn statements his legal team has collected.
"We have to turn the election over," Trump re-iterated. "All we need is to have some judge listen to it properly without having a political opinion or having another kind of problem."
Much of the hearing and most of the witness testimony focused on allegations that Republican poll observers had been forced to stand too far away from the ballot-counting process to determine if the ballots were legally cast.
"If you were a Republican poll watcher you were treated like a dog," Trump said. "But the Democrats had no problems. They were rough. They were literally pushed out."
Over the past three weeks, the Trump campaign mounted a legal challenge making that allegation, but the Pennsylvania courts ultimately rejected them. The Pennsylvania Supreme Court ruled against the Trump campaign's claims that poll watchers were not close enough to "meaningfully observe" the vote count.
In a vote of 5-2, the court found that elections officials followed the law in providing the Trump campaign sufficient access to the poll workers who were opening mail-in ballots. There are simply no requirements that say how close the observers need to be placed to watch the process, the court found.
"These provisions do not set a minimum distance" for observers to watch the process, Justice Debra Todd wrote for the majority. "The General Assembly, had it so desired, could have easily established such parameters; however, it did not."
And even those dissenting were not partial to the Trump campaign argument. In his dissenting opinion, Chief Justice Thomas G. Saylor wrote that the campaign's request to cancel large numbers of ballots "based on isolated procedural irregularities" was "misguided."
During his comments Wednesday, the president confirmed earlier reports that he has had difficulty securing a lawyer to take on the effort to contest the election.
"There are other lawyers that backed down because they were being screamed at," Trump said in praising the loyalty of Giuliani. "I told him the other day, Rudy, you were the greatest mayor … but what you're doing now is far more important. This is going to be your crowning achievement because you're saving our country."
During his presentation, Giuliani repeated other arguments that have also been swiftly dismissed by the courts – including the claim that the election should be invalidated because voters in Republican-majority counties were treated differently than those in Democratic-majority jurisdictions. A federal ruling stated those claims were "without merit."
"This Court has been presented with strained legal arguments without merit and speculative accusations, unpled in the operative complaint and unsupported by evidence," Judge Matthew W. Brann wrote. "In the United States of America, this cannot justify the disenfranchisement of a single voter, let alone all the voters of its sixth most populated state. Our people, laws, and institutions demand more."
That case is now on appeal.
Mark Aronchick, a Philadelphia lawyer who argued the case against Giuliani, said he will wait to hear what the appeals court says before he can declare any sort of victory in the legal battle.
"I will say from the rooftops that the American public should be immensely proud that we have an independent judiciary," Aronchick said. "We operate under the rule of law, and not the rule of the soapbox from the driveway of Four Seasons Total Landscaping."
The Republican lawmakers who hosted Wednesday's caucus meeting said they were eager to find a way to fix what they considered to be significant problems with the 2020 election. Giuliani urged them to find a way to invalidate the mail-in ballots.
"This election, the numbers don't add up," Giuliani said. "Count the honest votes and the winner of this election changes."
ABC News' Will Steakin and John Verhovek contributed to this report.