President Trump’s capacity to make things up is one of the defining features of his presidency. His loose adherence to the truth, when it suits his political purposes, seems to know few limits.

The president was at a roundtable discussion in West Virginia on Thursday for an event designed to highlight the new tax law, which Republicans are counting on to hold down expected losses in the November midterm elections.

Theatrically, he tossed aside the pieces of paper that were to be the highlights of his message. In going off script, he wandered into territory he had explored earlier in his presidency — the claim that there were millions of illegal votes cast in the 2016 election. It’s the reason, he said, that he lost the popular vote to Hillary Clinton.

But if his bottom line was unchanged, remarkably, he had a revised claim about what happened on Election Day. His earlier charge was that 3 million to 5 million people had voted illegally. He offered no evidence, and White House advisers were flummoxed when asked to back up what the president said because there was no proof.

Eventually, Trump used the baseless claim to order up a national commission to investigate what he insisted was widespread voter fraud in the United States. The commission was chaired by Vice President Pence, with Kansas Secretary of State Kris Kobach serving as vice chair, principal administrator and chief advocate of Trump’s assertion.

The commission quickly devolved into a pool of partisan wrangling and some months later was dissolved by the president. No evidence was ever discovered that the election had been marred by significant voter fraud.

Trump, however, cannot let go. On Thursday, he found his way back to the issue during a rambling discussion of illegal immigration, border security and his plan to send the National Guard to police the U.S. border with Mexico.

The Washington Post’s David Nakamura analyzes President Trump’s claims about “caravans” of immigrants heading toward the United States from Central America.

He argued that Democrats have a vested interest in the current immigration system, particularly the provision that allows family members of immigrants to apply for admission. “This is what the Democrats are doing to you,” he told the audience. “And they like it because they think they’re going to vote Democrat. Okay? Believe me, they’re doing that for that reason.” The audience applauded.

Trump said immigrants allowed into the country under the so-called chain or family migration provision would overwhelmingly vote for Democrats rather than Republicans. And then came this: “In many places, like California, the same person votes many times.” The audience laughed. “You probably heard about that. They always like to say, ‘Oh, that’s a conspiracy theory.’ Not a conspiracy theory, folks. Millions and millions of people.”

So now the claim is not just that 3 million to 5 million people voted illegally, but that millions and millions of people are voting many times each, in California alone.

It would be easy to dismiss all this as more of the same — mostly harmless commentary tossed out to an audience of supporters by the president — all in keeping with what he does. Yet each time he comes back to this particular claim, it strikes anew at one of the foundations of a democratic society. Every time he makes the accusation, he threatens to undermine confidence in the electoral system, which is already under assault by Russia and which will be tested anew in 2020.

Then there was the president’s week-long obsession with the “caravan” of migrants heading from Central America into Mexico and, as he tweeted, threatening to come across what he suggested was the porous U.S.-Mexico border. He made it sound like an invading army marching north. “ ‘Caravans’ coming,” he tweeted at the beginning of the week. “Republicans must go to Nuclear Option to pass tough laws NOW.”

He claimed Mexico had “absolute power” to stop the caravan from entering that country, so as to prevent it from passing through to the United States. In contrast, he said this country “has no effective border laws.” He claimed new legislation is needed to prevent the “massive inflow of Drugs and People.”

He later tweeted, “Caravans are heading here. Must pass tough laws and build the WALL. Democrats allow open borders, drugs and crime!” He said the caravan was heading toward “our ‘Weak Laws’ Border.” He then decided that, in the absence of the wall, he would order the National Guard to the border.

At his West Virginia event, Trump returned to something he had raised on the day he announced his candidacy in June 2015. At his announcement, he charged that Mexico was sending its worst people across the border illegally, including rapists. On Thursday, he brought charges of rapes to the story of the caravan, though in a different context, with women in the caravan as victims.

“Remember my opening remarks at Trump Tower, when I opened [the campaign],” he said. “Everybody said, ‘Oh, he was so tough,’ and I used the word ‘rape.’ And yesterday, it came out where, this journey coming up, women are raped at levels that nobody has ever seen before.” No one was quite sure where Trump came up with the claim, nor were his advisers able to provide evidence or background to support it.

On the day Trump was speaking, the caravan was beginning to break up. Some in the group were intent on reaching the border with the United States, where they hoped to be able to seek asylum. But others had no intention of staging the kind of invasion the president seemed to believe was imminent. The caravan appeared to be the same as it has been in recent years: no major threat.

The president credited Mexico’s “strong immigration laws” for the dispersal of the caravan and then returned to another theme since he became president, the fact that illegal border crossings were at historic lows. “Because of the Trump Administrations [sic] actions, Border crossings are at a still UNACCEPTABLE 46 year low,” he tweeted.

On Friday, the Wall Street Journal editorial page opined, “President Trump can’t seem to decide whether his border-control plan is a success or an imminent national crisis.” The Journal editors noted that the strong U.S. economy probably was attracting more immigrants (border crossings were higher last month than in March 2017). The editorial urged Trump to make a deal on immigration legislation, one that would trade greater security for changes to allow more legal immigrants. The editorial concluded with this: “Then he wouldn’t have to pull stunts like hyping a band of poor migrants as an invading army.”

Flying back from West Virginia on Thursday, the president answered a few questions from reporters. He was asked whether he had known about the $130,000 payment to adult-film star Stormy Daniels by Michael Cohen, his personal lawyer, shortly before the 2016 election. “No,” Trump replied. Daniels claims to have had a brief affair with the president more than a decade ago. The president told reporters to ask Cohen why the payment was made. He did not respond to a question about whether he had established a fund from which Cohen could draw money.

Perhaps all that is the truth.