“Despite our nation’s record of progress, and long tradition of extending voting rights – today, a growing number of citizens are worried about the same disparities, divisions, and problems that Dr. King fought throughout his life to address and overcome,” Holder said at an MLK Day event in Columbia, S.C.

Holder’s remarks in the Palmetto State come just weeks after the Justice Department blocked the state’s new voter ID law from taking effect, citing an unfair burden on minority voters.

Citing the “drumbeat of concern” he has encountered from Americans across the country about discrimination in the election systems, the attorney general vowed that the Justice Department was more committed than ever before to enforcing the Voting Rights Act.

Holder promised to continue reviewing recently proposed changes to the election system, including those that govern third-party voter registration organizations, early voting and photo identification requirements, with the goal of ensuring that there is “no discriminatory purpose or effect.”

“We need – and the American people deserve – election systems that are free from discrimination, free from partisan influence, and free from fraud,” said Holder. “And we must do everything within our power to make certain that these systems are more, not less, accessible to the citizens of this country.”

While insisting that voter fraud is simply “not acceptable,” Holder pointed out that making voter registration easier does not make elections more susceptible to fraud – a rationale that has been used by conservatives to push for strict voting laws.

“Protecting the right to vote, ensuring meaningful access, and combating discrimination must be viewed, not only as a legal issue – but as a moral imperative,” he said. “And ensuring that every eligible citizen has the right to vote must become our common cause.”

Civil rights groups such as the National Association for the Advancement of Colored People have been outspokenagainst the unprecedented number of voting restriction measures introduced in recent years.

They argue that the proposed laws amount to a coordinated assault on voting rights by specifically targeting minority groups such as African-American and Hispanic voters – communities that played a major role in electing President Barack Obama in 2008.

NAACP President Ben Jealous, who joined Holder in South Carolina on Monday, also vowed to continue fighting for the same justice that Dr. King had been a champion of.

“Your right to vote is the right upon which your ability to defend all of your other rights depends. When people come after your right to vote, it is usually to make it easier to come after so many of your other rights that you may actually hold dearer,” said Jealous, according to prepared remarks. “And when it comes to our right to vote we will not let any unjust law—or any person for that matter— turn us around.”