The president, who is trailing his Democratic opponent, Joe Biden, in the polls, has pushed aggressively for in-person voting despite the pandemic, even as state election officials have moved to expand access to mail-in ballots amid fears that long lines and close quarters at polling places could increase transmission of the virus.

Trump did not elaborate on what any such executive order on mail-in voting would entail.

But his suggestion that he has the right to wade into how elections are conducted in states runs counter to Republican orthodoxy. GOP lawmakers have in the past cited local election control for their opposition to congressional attempts to expand voting rights, as well as institute more stringent security measures.

And any order from the president to curb mail-in voting would surely face a flurry of challenges in court from voting rights groups.

On Monday, Trump touched on the subject of a potential executive order only briefly, but repeated unsubstantiated assertions that mail-in voting is subject to widespread fraud and vowed to mount a legal challenge to block Nevada from issuing mailed ballots to all active voters.

But the assertion comes amid ramped-up efforts by Trump in recent weeks to sow doubt about the reliability of mail in-voting and, by extension, the November election. He even went so far last week as to float delaying the election until it is safer to vote in person — something he is not constitutionally empowered to do.

He has repeatedly issued warnings of chaos surrounding the use of mail-in ballots, predicting that the upcoming general election will be “the greatest election disaster in history” and pointing to a pair of New York City primaries that have yet to be called more than a month later. Trump has also accused the U.S. Postal Service of being unprepared to handle a surge of mail-in ballots, though the agency rejected that notion earlier Monday.

Despite the president’s repeated insistence to the contrary, cases of election fraud in the U.S. are exceedingly rare, though experts acknowledge that there are some slightly higher fraud risks associated with mail-in balloting when proper security measures are not put in place.

In November, 42 states and the District of Columbia will effectively allow for, at a minimum, no-excuse absentee balloting — meaning any voter, regardless of age, health or location on Election Day will be able to vote by mail should they choose to do so.

Even Republicans in swing states like Florida and Pennsylvania have urged voters to cast their votes by mail, while Democrats in Congress are pushing for the inclusion of billions of dollars in the next coronavirus relief package to help facilitate mail-in voting this fall.

An analysis last month of voting in three states that routinely and proactively mail every voter a ballot found that officials identified an infinitesimal amount of potentially fraudulent ballots.