Although most opposition to implementing a nationwide vote-by-mail option has come from Republican circles, such a system would not advantage either major party, according to a study from Stanford University’s Democracy and Polarization Lab.
Several states, including Colorado, Hawaii, Oregon, Washington and Utah, have mail-in voting as an option, while California gives individual counties the option to implement it. With public health experts recommending against large gatherings during the coronavirus pandemic, advocates have called for the expansion of mail-in voting.
As most states phased the system in on a county-by-county basis, researchers compared results in counties that adopted a program to those within the same state that did not. They did not measure any partisan effect.
“By comparing counties that adopt a vote-by-mail program to counties within the same state that do not adopt the program, we are able to compare the election outcomes and turnout behavior of voters who have different vote-by-mail accessibility but who have the same set of candidates on the ballot for statewide races,” they wrote.