Nearly 17,000 registered Wisconsin voters — potentially more — were kept from the polls in November by the state’s strict voter ID law, according to a new survey of nonvoters by two University of Wisconsin political scientists. The survey, summarized on Monday on the university’s website, is certain to further roil an ongoing debate over whether Donald J. Trump’s narrow victory in Wisconsin over Hillary Clinton was a result of efforts to depress Democratic turnout. Mr. Trump defeated Mrs. Clinton by 22,748 votes out of more than 2.9 million ballots cast. The November turnout in Wisconsin, 69.4 percent of eligible voters, was the lowest in a presidential election year since 2000. The study summarized on Monday specifically does not make that claim, its principal author, Prof. Kenneth R. Mayer of the University of Wisconsin-Madison, said in an interview. But neither did he rule it out. “The survey did not ask any questions about how people would have voted or about their party identification,” he said. “But it’s certainly possible that there were enough voters deterred that it flipped the election.”
Wisconsin’s voter ID law, enacted in 2011 after Republicans took control of the legislature and the statehouse, requires citizens to show a driver’s license, a passport, a naturalization certificate or one of several other fairly uncommon documents before casting a ballot. A federal court blunted the impact of the law in 2016, ordering the state to give a free ID to any voter who asked for one, but the state’s implementation of that order was criticized as ineffective.
In Wisconsin and elsewhere, Republicans have argued that an ID requirement is necessary to combat an epidemic of fraudulent voting, although studies have repeatedly shown that illegal voting is exceedingly rare. Privately, some Republicans have allowed that the laws’ main intent is to keep people who often vote Democratic — the poor, the young and minorities — from going to the polls.