In Pennsylvania, for instance, nearly 30,000 ballots sent to voters in Allegheny County, which includes Pittsburgh, went to the wrong addresses.

The counties had provided the company with lists of tens of thousands of requests weeks in advance. The company’s inability to meet demand has underscored the stress that mail voting has put on the nation’s election process as the coronavirus pandemic curtails in-person voting. Midwest Direct is the primary outside provider of absentee ballots for 16 Ohio counties, though many also have their own in-house operations.

Midwest Direct is owned by two brothers, Richard Gebbie, the chief executive, and James Gebbie, the chairman. This summer they began flying a Trump 2020 flag above Midwest Direct’s headquarters on the west side of Cleveland. It was a curious juxtaposition — a company in the business of distributing absentee ballots through the mail showing a preference for a president who has spent months denigrating the practice of voting by mail.

“We have freedom to vote for who we want and support who we want,” Richard Gebbie said in an interview last month. “We fly a flag because my brother and I own the company and we support President Trump.”…