WASHINGTON — In an abrupt reversal, President Trump now is encouraging voters in the critical swing state of Florida to vote by mail after months of criticizing the practice, and only days after threatening to sue Nevada over a new vote-by-mail law.

His encouragement follows a surge in Democratic requests to vote for mail in Florida. Democrats currently have about 1.9 million Floridians signed up to vote by mail this November, almost 600,000 more than the Republicans’ 1.3 million, according to the Florida Secretary of State.

In 2016, both sides had about 1.3 million signed up before the general election.

“Whether you call it Vote by Mail or Absentee Voting, in Florida the election system is Safe and Secure, Tried and True. Florida’s Voting system has been cleaned up (we defeated Democrats attempts at change), so in Florida I encourage all to request a Ballot & Vote by Mail!,” Trump tweeted Tuesday.

White House press secretary Kayleigh McEnany rejected the notion that the president has changed his views. She said he supports absentee voting by mail for a reason, as opposed to states mailing out ballots to all voters regardless of whether they requested them. Most election officials say there is little effective difference between absentee voting and voting by mail.

More voters during this year’s primary elections opted to vote by mail, and several states relaxed restrictions for voting absentee through the mail. Trump himself voted by mail in the Florida primary earlier this year.

Five states have relied on mail-in ballots since even before the coronavirus pandemic raised concerns about voting in person, but there is no evidence to support Trump’s assertion that voting by mail leads to widespread fraud.

Trump has gone so far as to suggest by tweet that the November election should be delayed “until people can properly, securely and safely vote.”

States that use mail-in votes exclusively say they have necessary safeguards in place to ensure that a hostile foreign actor doesn’t disrupt the vote. Election security experts say voter fraud is rare in all forms of balloting, including by mail.

With Florida’s large retirement population, voting by mail is expected to become a more popular option this November. Sen. Marco Rubio, R-Fla., was asked Saturday if he had concerns about the option. “No, I’m not concerned about mail-in voting in Florida,” he said tersely.

Florida GOP officials welcomed Trump’s tweet.

“Thank you for the clarification Mr President! This is very helpful,” said Joe Gruters, the chair of Florida’s Republican Party. “Florida will deliver you the 29 electoral votes!”

Nevada lawmakers have recently passed a bill that would add the state to a growing list of U.S. states mailing active voters ballots ahead of the November election.

The bill, which was passed Sunday, was signed into law Monday by Gov. Steve Sisolak, a Democrat. Nevada joins seven states that plan on automatically sending voters mail ballots, including California and Vermont, which moved earlier this summer to adopt automatic mail ballot policies.

Trump called the bill’s passage “an illegal late night coup” in a tweet Monday morning. He accused Sisolak of exploiting COVID-19 to ensure votes in Nevada would favor Democrats.