President Trump announced Monday on his social media site that he plans to "lead a movement" to get rid of mail-in ballots and voting machines in the country ahead of next year's midterm elections.

Part of his plan, he wrote, includes signing an executive order that would bar states from using mail ballots and potentially some voting machines. He said — without evidence — that voting machines are "highly inaccurate," as well as more expensive than watermarked paper ballots.

Most U.S. voters already vote using paper ballots, and research has consistently found hand-counting ballots to be less accurate and more expensive than using machine tabulators. Trump, who's long spread baseless claims about the security of mail ballots, also falsely claimed that the U.S. is the only country that uses mail voting.

"We're going to start with an executive order that's being written right now by the best lawyers in the country to end mail-in ballots because they're corrupt," Trump said later Monday, during a meeting with Ukrainian President Volodymyr Zelenskyy at the White House. "And it's time that the Republicans get tough and stop it because the Democrats want it. It's the only way they can get elected."

Although Trump himself urged his supporters to vote using mail ballots prior to the 2024 election, Democrats have been significantly more likely to vote using mail-in ballots, compared to Republicans, since the 2020 election. That gap has only gotten wider in recent elections as GOP-led states have passed more restrictions on this method of voting.

But legal experts say Trump does not have the legal authority to tell states how to run their elections.

Michael Morley, a professor at Florida State University College of Law, told NPR that the Constitution gives Congress — not the president — the power to regulate federal elections.

"There's really nothing that the executive branch can do on its own in terms of direct mandates," he said.

Any changes to the president's legal authority would require action from Congress, said UCLA law professor Richard Hasen.

"Unless the president has some theory under which he could try to ban certain kinds of voting machines or tried to ban mail-in ballots by enforcing some existing federal law, he would need the cooperation of Congress," Hasen said, "which I think he'd be unlikely to get to have any kind of federal interference with how the midterm elections will be run."

David Becker, the executive director and founder of the nonpartisan, nonprofit Center for Election Innovation & Research, said the Founders deliberately gave the president no role in how elections are conducted.

"Hamilton foresaw, and made clear in Federalist 59 that a democracy must diversify power of elections in order to protect itself from an overzealous executive, and therefore power over elections would reside with the several states," he told NPR in a statement.

It would also be a logistical stretch to upend how states run their elections as midterm primaries get closer, said Matt Germer, director of the governance program at the right-of-center R Street Institute, a Washington-based think tank.

For one, any executive order is likely to face litigation, which could take a while to sort out. And then, states would have to likely pass new laws or implement new voting plans ahead of voting.

"In some places, I think things like restricting voting by mail mechanically would just mean forcing more people to come in and vote in person," Germer said. "And they need to make sure that they invest the resources in in-person voting to maybe account for that."

He said officials would have to find more locations to host polling places. And he said volunteers would need to be trained and facilitate those voting places.

"It would be a huge undertaking and I think realistically it's highly unlikely that he could end voting by mail or end the use of very particular voting machines in time for 2026 now," Germer said.

Barbara Smith Warner, executive director of the National Vote at Home Institute, which advocates for wide use of mail-in voting, said it would be nearly impossible to actually get rid of mail-in voting in such a short timeframe. But she said she believes the larger effort here is to "destabilize" next year's elections.

"Efforts to eliminate this are ignoring the facts and really are just trying to undermine confidence in our elections overall," she said. "This is yet another power grab of federal overreach into the states' rights to run their own election."

Hasen said Trump has tried to interfere in elections before by seeking to overturn the results of the 2020 election, which Trump lost, so he said "it would not be surprising" if he were again trying to interfere with a major election.

"And so now is the time to take preparations on the part of states and parts of courts and others to ensure that the elections that we conduct in 2026 will be conducted with fairness and integrity," Hasen said.