Why does Trump want to stop people from voting by mail?

“Election fraud in the United States is very rare, but the most common type of such fraud in the United States involves absentee ballots,” Rick Hasen, an election expert at the University of California, Irvine, law school, told the Times in April. “Sensible rules for handling of absentee ballots make sense, not only to minimize the risk of ballot tampering but to ensure that voters cast valid ballots.” The five states where voting by mail is the norm “report very little fraud,” the Times notes.