could benefit Democrats. Barber and political scientist John Holbein at the University of Virginia decided to test those claims by comparing voting behavior in counties that switched to universal mail-in voting (175 counties in 2018) with the nearly 3000 counties that didn’t. They also looked at voter behavior before and after each changeover.
They found that in presidential and midterm general elections between 1996 and 2018, switching to all-mail voting increased the percentage of residents who voted by 1.8% to 2.9%, they report today in Science Advances. When it came to the Democratic share of the vote, they found a tiny uptick in the share of votes that went to Democratic candidates for Congress, governor, and president—approximately 0.7%. But the difference was so small that the margin of statistical error means it’s possible there was no effect at all, Holbein says. “There might be a teensy, tiny effect on Democratic turnout.”
