Updated

Thousands commemorating the Martin Luther King Jr. holiday Monday outside South Carolina's capitol heard a message that wouldn't have been out of place during the halcyon days of the civil rights movement a half-century ago: the need to protect all citizens' right to vote.

A similar tone was struck at Ebenezer Baptist Church in Atlanta, where King preached from 1960 until his death. There and in South Carolina, speakers condemned the voter identification laws they said are meant to suppress black voter turnout.

For most of 13 years in South Carolina, the attention at the NAACP's annual rally has been on the Confederate flag that still waves outside the Statehouse. But on Monday, the civil rights group shifted the focus to laws requiring voters to show photo identification before they can cast ballots, which the group and many other critics say is especially discriminatory toward African-Americans and the poor.

South Carolina's new law was rejected last month by the U.S. Justice Department, but Gov. Nikki Haley vowed to fight the federal government in court. At least a half-dozen other states passed similar voter ID laws in 2011.

"This has been quite a faith-testing year. We have seen the greatest attack on voting rights since segregation," said Benjamin Todd Jealous, president of the National Association for the Advancement of Colored People.

The shift in tactics was also noted by the keynote speaker, U.S. Attorney General Eric Holder. Last month, Holder said the Justice Department was committed to fighting any laws that keep people from the ballot box. He told the crowd he was keenly aware he couldn't have become the nation's first African-American attorney general without the blood shed by King and other civil rights pioneers.

"The right to vote is not only the cornerstone of our governance, it is the lifeblood of our democracy. And no force has proved more powerful, or more integral to the success of the great American experiment, than efforts to expand the franchise," Holder said. "Let me be very, very clear — the arc of American history has bent toward the inclusion, not the exclusion, of more of our fellow citizens in the electoral process. We must ensure that this continues."

Texas' new voter ID law is currently before the Justice Department, which reviews changes in voting laws in nine mostly Southern states because of their history of discriminatory voting practices. Other states that passed such laws in 2011 included Alabama, Kansas, Mississippi, Rhode Island, Tennessee and Wisconsin.

Similar laws already were on the books in Georgia and Indiana, and they were approved by President George W. Bush's Justice Department. Indiana's law, passed in 2005, was upheld by the U.S. Supreme Court in 2008.

Critics have likened the laws to the poll taxes and tests used to prevent blacks from voting during the civil rights era. Supporters, many of whom are Republicans, say such laws are needed to prevent fraud.

"I signed a bill that would protect the integrity of our voting," Haley said in a statement welcoming Holder to South Carolina.

At the Atlanta church where King once preached, the Rev. Raphael G. Warnock said some in America disrespect King's legacy by "cutting off those for whom he died and the principles for which he fought."

He called voter ID laws an affront to the memory of the civil rights leader.

"You cannot celebrate Dr. King on Monday, and undermine people's ability to vote on Super Tuesday," Warnock said.

The King Day rally in South Carolina took place in the shadow of Saturday's Republican presidential primary. State NAACP President Lonnie Randolph said people should vote any time they can, but said his group is nonpartisan. He said officials wouldn't encourage its members — a generally Democratic voting bloc — to disrupt the GOP's process of choosing its nominee because "we don't do the mean things."

Jealous made one of the few references to the GOP field during Monday's rally, saying he was tired of attacks on the movement, such as cuts to education funding.

"And I'm real tired of dealing with so-called leaders who talk out of one side of their mouth about celebrating the legacy of Dr. King and then do so much out the other side of their mouth to block everything the man stood, fought and died for," Jealous said.

The King Day rally in South Carolina was first held in 2000 to call for the Confederate flag to come down off the capitol dome, and has continued after state leaders decided instead to place the flag on a 30-foot pole on the Statehouse lawn near a monument to Confederate soldiers.

The flag was mentioned Monday — North Carolina NAACP president the Rev. William Barber called it a "terrible, terroristic banner" — but it was not the focus.

The Confederate flag and voter ID laws are all examples of how blacks cannot stop fighting for civil rights, said 39-year-old Llewlyn Walters of Columbia, whose grandmother watched King speak and whose mother told him stories of the civil rights movement as he grew up.

"People's hearts and minds change, but then they forget. The movement was great, but that one single generation couldn't stop all the discrimination in this country any more than one single dose of antibiotic can fight a disease," Walters said.

In Washington, President Barack Obama and his family commemorated the day by helping to build bookshelves in a local school's library. The president said there was no better way to celebrate King's life than to spend the day helping others.

Obama's attorney general ended his speech on a positive note, saying Americans can't forget the progress this nation has made. After all, the nation elected a black president just 40 years after King was assassinated.

"In the spirit of Dr. King, let us signal to the world that, in America today, the pursuit of a more perfect union lives on," Holder said. "The march toward the Promised Land goes on, and the belief not merely that we shall overcome, but that, as a nation, we will all come together, continues to push us forward."

___

Associated Press writers Jessica Gresko in Washington and Errin Haines in Atlanta contributed to this report.