Boxes of illegal and legal vote-by-mail ballots at the Miami-Dade County Elections Department ahead of Florida’s Aug. 18 primary election.AP Photo/Lynne SladkyMichael Herron, Dartmouth College and Daniel A. Smith, University of FloridaTens of millions of Americans have already cast their ballots for the 2020 election by mail, building on a historic shift in voting methods that started with primary elections held during the COVID-19 pandemic.Mail-in ballots, however, aren’t automatically accepted as in-person ballots are. Rather, they can be rejected if they have signature defects on their retu…
