Wisconsin is the only state that requires students to have ID with five necessary pieces of information and proof of school enrollment.
Judge Nelva Gonzales Ramos said that evidence "establishes that a discriminatory purpose was at least one of the substantial or motivating factors behind passage" of the measure.
North Carolina law scrapped by federal appeals court targeted "African Americans with almost surgical precision."
The court denied a request filed by opponents of the law, including individual Texas voters, who say the law is not needed and disproportionately affects older and poorer voters.
It was a key victory for Republicans in a presidential election year who say the law is needed to prevent fraud.