The Supreme Court, in halting enforcement of the federal government's most potent tool against voting discrimination, turned to Congress to draft new rules to determine which states and localities must get Washington's approval to alter election laws.

But with Capitol Hill gridlocked by partisan politics, a replacement provision isn't expected this Congress or for many years, essentially neutering a central tenet of the landmark 1965 Voting Rights Act --though one many argue is outdated and unnecessary.

"I don't think Congress can agree on what time to adjourn on a particular day, much less how to reform America's voting rights' laws," said Jamin Raskin, a constitutional law professor at the American University Washington College of Law.

"The reality is, certainly nothing is going to happen this Congress, and it's hard to see how the Voting Rights Act gets resuscitated after this blow."

But Senate Judiciary Committee Chairman Patrick Leahy, D-Vt., vowed to do just that. He said he plans to introduce a bill as early as July that will "respond" to the 5-4 ruling, although he would not say specifically what he hopes to include in the legislation.

Leahy said the law should not be gutted by "five justices who decide they know a lot better" than the hundreds of lawmakers who voted for the law nearly five decades ago and reauthorized it in 2006.

President Obama said the the ruling was a major setback in the nation's push to end voting discrimination and called on Congress to pass legislation "to ensure every American has equal access to the polls."

While the justices left in place most of the Voting Rights Act, they threw out key rules that required all or parts of 16 states, mostly in the South, to seek approval from the Justice Department or a federal court before they make changes in the way they hold elections.

Shelby County, Ala., challenged the constitutionality of the the advanced approval, or "preclearance" requirement, saying it no longer should be forced to live under oversight from Washington because it has made significant progress in combating voter discrimination.

Chief Justice John Roberts, who wrote the majority opinion on the case, argued that lawmakers have failed to modernize the requirement, saying, "Congress must ensure that the legislation it passes to remedy that problem speaks to current conditions."

But preclearance backers say without it, states might seek to reinstate or push a new wave of discriminatory voting measures previously blocked or deterred by the law.

"The centerpiece of the Voting Rights Act was placing the burden of changes in voting practices on the most troubled jurisdictions, rather than placing the burden on disenfranchisedgroups to go to court," Raskin said. "Now [the high court] has pulled the rug underneath that innovation, and like quick sand many parts of the country will begin to sink back to the old baseline of racially infused elections."

One option would be for Congress to extend the preclearance requirement to the entire nation. The approach would have traction with Republicans who oppose the notion that some states are singled out in the law. But the Obama administration likely would oppose such a move, as it would place heavy strains on the Justice Department's enforcement capabilities.

Groups and individuals still can challenge state and local voting procedures they deem unfair or illegal under the Voting Rights Act. But the burden of proof now will be on them, unlike preclearance, in which affected jurisdictions had to prove to the federal government they were running fair elections.

Sean Lengell, Congressional Correspondent