Last week, around the time North Carolina’s voter ID law was going before a federal judge in Winston-Salem, researchers from the University of California-San Diego released a damning study of such laws around the country. In short, the report stated the obvious: these laws keep minorities from voting.

In “Voter Identification Laws and the Suppression of Minority Votes,” UCSD political scientists Zoltan Hajnal, Nazita Lajevardi, and Lindsay Nielson argued that “strict photo identification laws have a differentially negative impact on the turnout of Hispanics, Blacks, and mixed-race Americans in primaries and general elections.”

When a state has a strict voter ID law, African-Americans and Latinos are much less likely to vote. The voter-participation gap between both whites and Latinos and whites and African-Americans in states with these laws is roughly twice as large as in states without them.

“When [voter ID laws] are enacted, racial and ethnic minorities are less apt to vote,” they wrote. “An already significant racial skew in American democracy becomes all the more pronounced.” (In states that merely “requested” identification rather than requiring it, no significant impact was found.)

The UCSD study stretches from 2006 to 2012, which means it doesn’t include North Carolina’s law, passed in 2013 and considered at the time one of the most stringent in the nation. (Fearful that a court would invalidate the law, lawmakers last year amended it to allow for alternative forms of ID or a “signed affidavit” showing why a voter couldn’t access proper identification.)

As in other states, officials professed concern about electoral integrity. Former state House Speaker Thom Tillis and Senate President Phil Berger touted it as a response to “widespread” voter fraud in the 2012 election, but that claim has long since been debunked. In 2014, a Loyola University law professor found evidence for just 31 cases of fraud in more than 1 billion votes cast nationwide since 2000.

Being charitable, what you have here is a solution in search of a problem. Being less charitable, perhaps for the lawmakers in the 36 states that have passed voter ID laws (three of which have been struck down), this solution’s consequences are a feature, not a bugand the data suggests that it’s working.