The first is that the November elections will very likely be a “mostly mail” election whether anyone likes it or not — even if no laws are changed. Twenty-nine states already have no-excuse absentee voting, including the states where control of the White House and the Senate will be decided: Wisconsin, Michigan, Pennsylvania, Florida, Arizona, North Carolina, Georgia, Iowa, Montana, and Maine. In April, when Wisconsin held its Democratic primary, only one-quarter of voters cast ballots in person on Election Day. If voters are concerned about the coronavirus, and there’s every reason to believe it will still be a threat in November, the overwhelming majority will choose early mail-in or curbside voting.
The second thing to keep in mind is that expanded mail-in and early-voting will not necessarily hurt Republicans in November. The GOP just won an all-mail special election in California. Colorado Republican Cory Gardner won his first term in the Senate in 2014 in an all-mail election. In 2018, 79 percent of ballots were cast in Arizona by mail. Republican governor Doug Ducey won re-election by 14.2 points even as Republican senator Martha McSally lost by 2.4 points.
So Republicans can win in mail or mostly-mail elections, and at any rate it’s unlikely that many states will transition to California-style all-mail states before November.