Earlier in the week (27/05/2020), Trump denounced state election...

Earlier in the week (27/05/2020), Trump denounced state election officials in Michigan and Nevada, claiming (falsely) that they were sending out ballots for the November election, and that this was for the purpose of vote fraud.

He threatened to cut off all federal funds to the state of Michigan, although the president has no such power under the Constitution.The two states had announced plans to send out applications for mail ballots to all registered voters.
The actual ballots would be sent only to those who sent in signed statements that they wished to vote by mail.
https://www.wsws.org/en/articles/2020/05/27/elec-m27.html