A landmark Supreme Court ruling that struck down a key part of the Voting Rights Act has set up a stand-off between Republican-led states and the Obama administration over controversial voting laws that until now had been stalled.

The 5-4 ruling on Tuesday addressed a 1960s-era provision that largely singled out states and districts in the South -- those with a history of discrimination -- and required them to seek federal permission to change their voting laws.

The court ruled that the formula determining which states are affected was unconstitutional.

In doing so, the court potentially opened the door for certain states to proceed with voter ID laws and other efforts that to date had been held up because of the Voting Rights Act. Prominent among those are voter identification laws in Alabama and Mississippi.

Texas Attorney General Greg Abbott also put out a lengthy statement vowing to proceed with both a voter ID law and potentially a new set of redistricting maps without federal oversight.

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"Today's ruling ensures that Texas is no longer one of just a few states that must seek approval from the federal government before its election laws can take effect," he said. "With today's decision, the state's voter ID law will take effect immediately. Redistricting maps passed by the Legislature may also take effect without approval from the federal government."

Attorney General Eric Holder warned states against going too far. He said the Justice Department would not hesitate to take "swift" action against states looking to "take advantage" of the ruling.

He, like President Obama, said he was "deeply disappointed" in the decision, saying discriminatory practices live on and need to be addressed.

"These problems have not been consigned to history," Holder said.

Holder and Obama urged Congress to create a new formula.

"Today's decision invalidating one of its core provisions upsets decades of well-established practices that help make sure voting is fair, especially in places where voting discrimination has been historically prevalent," Obama said.

But their statements acknowledged that until Congress intervenes, officials' hands are largely tied when it comes to screening particular states.

The court effectively determined that the law, which Congress most recently renewed in 2006, relied on old data that does not reflect racial progress and changes in U.S. society.

"In 2006, the Act was reauthorized for an additional 25 years, but the coverage formula was not changed. Coverage still turned on whether a jurisdiction had a voting test in the 1960s or1970s, and had low voter registration or turnout at that time," Chief Justice John Roberts wrote.

He clarified that the provision requiring advance approval of voting law changes -- known as Section 5 -- was not being struck down. Rather, the court found that the provision pertaining to the formula, known as Section 4, was unconstitutional.

The decision, though, challenges the overall practice of federal screening unless and until Congress addresses the formula.

The decision means that a host of state and local laws that have not received Justice Department approval or have not yet been submitted will be able to take effect.

Going forward, the outcome alters the calculus of passing election-related legislation in the affected states and local jurisdictions. The threat of an objection from Washington has hung over election-related proposals for nearly a half century. At least until Congress acts, that deterrent now is gone.

Roberts argued that these states and the conditions in them have "changed dramatically" over the years.

"The tests and devices that blocked ballot access have been forbidden nationwide for over 40 years. Yet the Act has not eased (Section 5's) restrictions or narrowed the scope of (Section 4's) coverage formula along the way. Instead those extraordinary and unprecedented features have been reauthorized as if nothing has changed, and they have grown even stronger," Roberts wrote.

The court warned of problems with the voting rights law in a similar case heard in 2009. The justices averted a major constitutional ruling at that time, but Congress did nothing to address the issues the court raised. The law's opponents, sensing its vulnerability, filed several new lawsuits.

The latest decision came in a challenge to the advance approval, or preclearance, requirement, which was brought by Shelby County, Ala., a Birmingham suburb.

The lawsuit acknowledged that the measure's strong medicine was appropriate and necessary to counteract decades of state-sponsored discrimination in voting, despite the Fifteenth Amendment's guarantee of the vote for black Americans.

But it asked whether there was any end in sight for a provision that intrudes on states' rights to conduct elections, an issue the court's conservative justices also explored at the argument in February. It was considered an emergency response when first enacted in 1965.

The county noted that the 25-year extension approved in 2006 would keep some places under Washington's oversight until 2031 and seemed not to account for changes that include the elimination of racial disparity in voter registration and turnout or the existence of allegations of race-based discrimination in voting in areas of the country that are not subject to the provision.

The Obama administration and civil rights groups said there is a continuing need for it and pointed to the Justice Department's efforts to block voter ID laws in South Carolina and Texas last year, as well as the redistricting plan in Texas that a federal court found discriminated against the state's large and growing Hispanic population.

Advance approval was put into the law to give federal officials a potent tool to defeat persistent efforts to keep blacks from voting.

The provision was a huge success because it shifted the legal burden and required governments that were covered to demonstrate that their proposed changes would not discriminate. Congress periodically has renewed it over the years. The most recent extension was overwhelmingly approved by a Republican-led Congress and signed by President George W. Bush.

The requirement currently applies to the states of Alabama, Alaska, Arizona, Georgia, Louisiana, Mississippi, South Carolina, Texas and Virginia. It also covers certain counties in California, Florida, New York, North Carolina and South Dakota, and some local jurisdictions in Michigan. Coverage has been triggered by past discrimination not only against blacks, but also against American Indians, Asian-Americans, Alaska Natives and Hispanics.

Towns in New Hampshire that had been covered by the law were freed from the advance approval requirement in March. Supporters of the provision pointed to the ability to bail out of the prior approval provision to argue that the law was flexible enough to accommodate change and that the court should leave the Voting Rights Act intact.

The Associated Press contributed to this report.