The answer, it turned out, was that Mangeni’s signature on the ballot didn’t match the one he used when he registered to vote. Ohio, like 30 other states, uses signature matching as a fraud-prevention measure. Mangeni sometimes uses different signatures, and he didn’t recall which one he used to register. Under Ohio law, election officials are supposed to mail a notice to any voter whose ballot is rejected, giving them a chance to correct an error, but Mangeni said he never received a notification. His name did, however, go into a spreadsheet at the Ohio secretary of state’s office, which is how the ACLU found it. Mangeni agreed to become a plaintiff in a suit challenging Ohio’s signature-matching law.

“I felt cheated out of something,” Mangeni told me. Besides, “it was irritating. Some of the people that won the elections, I didn’t vote for.”

If Mangeni felt irritated, a voter who has her ballot rejected in the general election, especially in a tightly contested swing state such as Ohio, is likely to feel something closer to full-on rage. A political scientist at Carroll College, working on behalf of plaintiffs challenging Ohio’s signature-matching law, found that 97 percent of rejected signatures are likely to be authentic—or, for every invalid ballot, 32 valid ones are thrown out.