“I have the right to do it,” Trump told reporters at a White House press conference. “We haven’t gotten there yet, we’ll see what happens.”

Trump added that Republicans are planning to file suit as soon as Tuesday to try to block Nevada’s expansion of mail-in voting.

Nearly all election procedures are governed on a state-by-state basis, with the remainder set by Congress or enshrined in the Constitution. There is no precedent or apparent authority for Trump to try to curtail the use of mail-in ballots by executive order, though he could use a document to formalize his opposition to the practice.

Trump’s claimed authority comes days after he publicly floated a delay to the Nov. 3 presidential election, a notion was met with swift bipartisan blowback.