“Election fraud in the United States is very rare, but the most common type of such fraud in the United States involves absentee ballots,” Mr. Hasen said. “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.”
States that vote entirely by mail see little fraud.
Five states, including the Republican bastion of Utah, now conduct all elections almost entirely by mail. They report very little fraud. The state is among the six states with the highest percentage of mail-in votes in the last election in 2018, all of which had Republican state election supervisors at the time, according to David J. Becker, the director of the Center for Election Innovation and Reform.
Colorado, which has 3.5 million registered voters, has been a vote-by-mail state since 2014.
“There’s just very little evidence that there is more than a handful of fraudulent (vote-by-mail) cases across the country in a given election cycle,” said Judd Choate, the director of elections in the Colorado Department of State.
Republicans say voting by mail gives Democrats an advantage.
Since the coronavirus outbreak and calls for more widespread mail voting to protect voters, some Republican officials, including Mr. Trump, have advanced another argument against the practice: that it will disadvantage Republican candidates.
The president on Wednesday tweeted that mail-in voting “for whatever reason, doesn’t work out well for Republicans.” In Georgia, where the secretary of state is mailing all voters absentee ballot requests for the May primary, the State House speaker, David Ralston, a Republican, told a local news site, “This will be extremely devastating to Republicans and conservatives in Georgia,” adding, “This will certainly drive up turnout.”
Even before the coronavirus emerged as a global threat, Democrats had generally favored ways to expand access to voting by mail. Some Republicans have long argued against voting by mail and in favor of tightening voter identification and registration requirements, asserting that easing restrictions invites voter fraud.
Some Democrats have also raised concerns about security.
While Democrats have generally favored mail voting — which works in a very similar way to absentee voting — some have balked at its widespread use because of the reduced level of security when voters are not required to appear at the polls.