Concern over voting rights continues across the nation, and the latest state to face Justice Department intervention is South Carolina.

The U.S. Department of Justice blocked a South Carolina law earlier this week that would have required voters to present photo identification at polling stations, on the grounds that the law would disproportionately affect minority voters. Because of the state’s history with racial discrimination, South Carolina is one of the states that falls under the Voting Rights Act (VRA) and must obtain pre-clearance from the Justice Department regarding any new voting requirements. The Justice Department must certify that any new laws aren’t discriminatory in their impact, not just in their. South Carolina has one of the highest concentrations of African-Americans in the United States.

According to South Carolina’s government records, about 240,000 registered voters do not have a proper photo ID. What makes the state’s attempt to use photo identification so insidious is that the people who are least likely to have a proper photo ID are usually Black, young or poor and tend to vote Democrat at the polls. The law, passed by the Republican-dominated legislature and signed by Conservative favorite Nikki Haley, would require all voters to present photo identification at the ballot box. Haley and her conservative allies claim the law is meant to protect against voter fraud.

“The absolute number of minority citizens whose exercise of the franchise could be adversely affected by the proposed requirements runs into the tens of thousands,” wrote Assistant Attorney General Thomas E. Perez in a letter to South Carolina legislators

Civil rights groups like the NAACP and Democratic politicians argue that the law and others like it around the country intentionally seek to suppress minority and young voter turnout because they are the two groups least likely to have photo ID, giving Republicans an edge in races in the state.

South Carolina Republicans have not been alone in this tactic. In the presidential swing states of Wisconsin and Indiana, legislators have also pushed voter ID laws without any significant evidence of voter fraud. In the case of those two Midwestern states, the ACLU jumped in to file a lawsuit claiming the requirement for photo identification was in effect a 21st century poll tax.