Sixty percent of voters — nearly 70 million people — are projected to vote by mail nationwide during the coronavirus pandemic. Those who study absentee rejection rates estimate that 1 percent to 2 percent of those votes — potentially more than 1 million — won't count, which could make a difference in battleground states.
"The vote-by-mail ballot rejections are going to be the hanging chads of 2000," said Daniel Smith, a professor of political science at the University of Florida.
The risk of ballot rejection varies by demographics and geography. The rate of rejection tends to be higher for Black, Hispanic, female and younger voters, as well as for people who don't usually vote by mail.