Last week, the 2016 presidential campaign officially kicked off with U.S. Senator Ted Cruz of Texas announcing his candidacy. On the same day the U.S. Supreme Court declined to review a case from the U.S. Court of Appeals for the Seventh Circuit upholding a Wisconsin statute—ushered into law by presumed 2016 candidate and current Wisconsin Governor Scott Walker—that conditions the right to vote on production of government-issued photo identification by the prospective voter.

Photo identification voting requirements have generated enormous controversy around the country and frequent litigation, highlighted by the 2008 Supreme Court decision in Crawford v. Marion County Election Board1 upholding an Indiana photo-identification requirement. Supporters of voter-ID laws claim they are intended to prevent voter fraud (though there is little or no evidence that voter fraud is a significant problem), while opponents argue the laws are intended to suppress the vote of minority voters (though there are few studies documenting the impact of such laws).