"By mailing applications, we have ensured that no Michigander has to choose between their health and their right to vote", Benson, a Democrat, said on Tuesday.
A Columbia University study indicates there's little evidence of vote fraud in the United States, with most such claims attributable to "false claims by the loser of a close race, mischief and administrative or voter error".
Trump was referring to Michigan Secretary of State Jocelyn Benson's announcement Tuesday that she was mailing absentee ballot applications - not the actual ballots - to all 7.7 million active voters in the state.
"This was done illegally and without authorization by a rogue Secretary of State", the president tweeted. "Sorry, but you must not cheat in elections", the president said. "I will ask to hold up funding to MI if they want to go down this Voter Fraud path!"
In a tweet Wednesday, Trump falsely claimed the state was sending ballots, not ballot applications, and said its federal funding was at risk. "Just like my GOP colleagues in Iowa, Georgia, Nebraska and West Virginia, '" she tweeted.
Two-thirds of MI voters approved a 2018 constitutional amendment that permits no-excuse absentee voting. Multiple states have rescheduled their spring primaries as the number of confirmed cases of Covid-19 keeps climbing.
Trump narrowly won MI in 2016, giving him the Electoral College votes needed to become president.
States have broad powers on setting rules for voting.
Yet, Trump may have jumped the gun on the threat to withhold the battleground state's funding, however, as only applications for ballots are being sent to voters - not the ballots themselves, as he tweeted.
The pandemic has prompted new attempts to expand mail-in voting, a trend that has been slowly building over the last two decades.
"Mail ballots - they cheat. OK?"
"Because I'm allowed to".
Some polling places in states that held primaries on March 17 were hastily closed; at others, workers scrambled to disinfect voting machines and keep people 6 feet apart in line. "Because I happened to be in the White House and I won't be able to go to Florida and vote", he said at the time. Almost two dozen other states conduct mail in balloting for lesser elections like school board.
Trump tweeted earlier in April that Republicans should stand against mail-in ballots, "Republicans should fight very hard when it comes to state wide mail-in voting".
"The biggest challenge I have right now is making the concept of absentee voting less toxic for Republicans", Kentucky Secretary of State Michael Adams, a Republican, recently told NPR.