Wisconsin Center for Investigative Journalism:

A UW-Madison study commissioned by Dane County Clerk Scott McDonell in 2017 estimated that thousands of registered voters in Dane and Milwaukee counties were deterred or prevented from voting because of the photo ID requirement in the 2016 presidential election — a situation that more heavily affected low-income people and African-Americans. The survey was mailed to 2,400 registered voters; 293 were returned.

Based on the sampling weight, UW-Madison political science professor Kenneth Mayer concluded that between 11,701 and 23,252 people did not vote due to confusion over voter ID requirements or lack of proper identification.

Trump won Wisconsin by 22,748 votes.

Mayer’s conclusion was challenged by a free market, limited government legal group, which contended there was no proven linkage between the photo ID requirement and the election results. Will Flanders, research director at the Wisconsin Institute for Law and Liberty, said the study “pushed a narrative” of voter suppression but did not actually prove it.

“The most this survey can claim to prove is that the administration of the law could have been improved or that the candidates could have run better ground games,” Flanders wrote.

But, with the 2018 general election approaching, stories like Brooke Evans’ show how easily confusion about voting can jeopardize voting. If it were not for her own efforts to help homeless students, Evans said, she herself might not have been able to vote.