At issue is whether states choose to categorize their mail-in ballots as first-class mail or marketing mail, the latter of which carries about one-third of the cost but gets lower priority.

“At a time when people will have to vote by mail in record numbers because they can’t or won’t go vote in person, the postmaster general is saying we should triple the rate of cost to vote by mail?” Mr. Schumer said. “What a despicable derogation of democracy.”…

The Postal Service responded that Mr. DeJoy had merely been suggesting to local elections officials how they could most efficiently carry out a vote-by-mail election, not mandating increased costs.

Martha Johnson, a spokeswoman for the agency, said the Postal Service “strongly” recommends that states and local governments choose to mail their ballots to voters at the higher rate, since they would typically then be delivered in two to five days. Marketing mail, by contrast, may take three to 10 days, she said.