COLUMBIA, S.C. In his bluntest comments to date, Attorney General Eric Holder said Monday that voting rights, particularly for minorities, are under assault in some states.

Speaking at a Martin Luther King Jr. Day event in Columbia, Holder said some states had sued to challenge provisions of the Voting Rights Act and had approved new laws that would make it difficult for some minorities to register and vote this year, five decades after King and other civil rights leaders fought for access to the ballot box.

"Each of these lawsuits claims that we've attained a new era of electoral equality, that America in 2012 has moved beyond the challenges of 1965 ... ," Holder told hundreds who gathered outside the domed Capitol. "I wish that were the case. But the reality is that - in jurisdictions across the country - both overt and subtle forms of discrimination remain all too common."

He added: "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. And ensuring that every eligible citizen has the right to vote must become our common cause."

Holder's comments come nearly four weeks after the Justice Department's Civil Rights Division ruled that South Carolina's voter identification law was discriminatory because it would make voting harder for minorities, who lack sufficient forms of government-approved ID more often than whites do.

Justice Department officials weighed in on the law under Section 5 of the 1965 Voting Rights Act, which requires approval of proposed voting-law changes in 16 mostly Southern states because they have histories of discrimination.

"We'll also continue to review other types of changes to our election systems and processes - including to the procedures governing third-party voter registration organizations, to early voting procedures and to photo identification requirements - to ensure that there is no discriminatory purpose or effect," Holder said.

South Carolina is one of 13 mostly Republican-controlled states that have approved new voting laws that include requiring government-approved photo ID to register or vote, shortening early voting periods and curtailing voter registration efforts by third-party groups such as the League of Women Voters or the NAACP.

In North Carolina, Gov. Bev Perdue vetoed a bill in June that would have required North Carolina voters to show a photo ID. The House failed to override the veto in July, but Republicans used a legislative maneuver to keep the bill alive for reconsideration this year.

Supporters of the new laws say they're needed to protect against voter fraud. Several studies and investigations - including a five-year probe by President George W. Bush's Justice Department - indicate that voter fraud in the United States is negligible, however.

Opponents view the new laws as a thinly veiled attempt to suppress the votes of minorities, the elderly and the young - key voting blocs for the Democratic Party.

An October study by New York University's Brennan Center for Justice estimated that the new laws would adversely affect more than 5 million voters nationwide, mostly minorities who lack sufficient government-sanctioned photo IDs or the materials to obtain the IDs.

"The spate of recent laws - the state ID laws, the laws that cut out voting on Sundays. The rationale of voter fraud - when we know the evidence of significant voter fraud is zero," said Norman Ornstein, a political research scholar at the American Enterprise Institute. "I'm left with the conclusion that it's an attempt to shape the electorate. I really view these as a modern-day equivalent of a poll tax."

Most of the Republican presidential contenders have derided the Justice Department's ruling on South Carolina's voter law as unwarranted federal meddling.

Former House Speaker Newt Gingrich, former Sen. Rick Santorum and Texas Gov. Rick Perry have accused the Obama administration of turning a blind eye to voter fraud and President Barack Obama's re-election campaign of trying to steal the 2012 election.