The liberal Supreme Court Justice Ruth Bader Ginsburg issued a blistering dissent Saturday after the high court ruled that Texas can use a controversial voter ID law this coming election.

The Texas legislature passed the law requiring voter ID at the polls fully knowing it would have a disproportionate impact on black and Hispanic voters, Ginsburg wrote in her dissent. More from her dissent:

"The greatest threat to public confidence in elections in this case is the prospect of enforcing a purposefully discriminatory law," she wrote, "one that likely imposes an unconstitutional poll tax and risks denying the right to vote to hundreds of thousands of eligible voters."

The Texas legislature knew the law could potentially stop 600,000 people from voting but rejected a number of amendments that would have reduced the impact on minorities — including an amendment that would have allowed additional forms of ID, Ginsburg wrote.

Voter ID laws have largely been backed by conservatives, who argue that they prevent fraud. Opponents of these laws point out that mass voter fraud is not a real phenomenon in the US. In fact, opponents say, voter ID laws are a thinly disguised attempt to keep lower-income blacks and Hispanics (who were less likely to have IDs) away from the polls since they'll likely vote for Democrats.