WASHINGTON - The Supreme Court on Tuesday ruled parts of the Voting Rights Act of 1965 were unconstitutional in a 5-4 vote, saying that Congress had not provided adequate justification for subjecting only nine states, including Mississippi, to federal oversight.

The majority opinion, written by Chief Justice John G. Roberts Jr., says:

"Our decision in no way affects the permanent, nationwide ban on racial discrimination in voting found in [Section] 2. We issue no holding on [Section] 5 itself, only on the coverage formula. Congress may draft another formula based on current conditions."

He also wrote in the opinion, "In 1965, the states could be divided into two groups: those with a recent history of voting tests and low voter registration and turnout, and those without those characteristics.

"Congress based its coverage formula on that distinction. Today the nation is no longer divided along those lines, yet the Voting Rights Act continues to treat it as if it were."

The court divided along ideological lines, and the two sides drew sharply different lessons from the history of the civil rights movement and gave very different accounts of whether racial minorities continue to face discrimination in voting.

President Barack Obama, whose election as the nation's first black president was cited by critics of the law as evidence that it was no longer needed, said he was "deeply disappointed" by the ruling.

"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," he said.

The decision will have immediate practical consequences. Changes in voting procedures that had required advance federal approval, including voter identification laws and restrictions on early voting, will now be subject only to after-the-fact litigation.

"With today's decision," said Greg Abbott, Texas' attorney general, "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."

Roberts said Congress remained free to try to impose federal oversight on states where voting rights were at risk, but must do so based on contemporary data. When the law was last renewed, in 2006, Congress relied on data from decades before to decide which states and localities were covered. The chances that the current Congress could reach agreement on where federal oversight is required are small, most analysts say.

Philadelphia Mayor James A. Young, the first African-American to be elected mayor of the majority-white city four years ago and re-elected in June when he defeated a white Republican, said elections don't need to be left to each individual state or county.

"I don't think we've gotten to that point yet," said Young, a Democrat. "I've been in politics for 22 years and every election is a new challenge of people doing something a little bit unethical. I just think we need the laws and we need to be monitored. I don't think we are ready yet to be on our own."

U.S. Rep. Gregg Harper (R-Miss.) issued the following statement in response to the decision:

"The 'Voting Rights Act' had no provision for removing a jurisdiction from its preclearance requirements even after a state, such as Mississippi, has demonstrated years of compliance and dramatic improvements in its voting patterns. The Supreme Court today recognized this flaw."

Young said he's for oversight. "It is easy to deprive or intimidate when it comes to voting," Young said.

"I think we do need some checks and balances whether it be state or federal. I don't think we ever need to depend upon the majority of honest men to run elections.

"They are becoming far and few with all the party bickering and everybody jockeying for position. Somebody has to watch us to make sure that we do it right, whether it's the Supreme Court or some other group. "

Justices Antonin Scalia, Anthony M. Kennedy, Clarence Thomas and Samuel A. Alito Jr. joined the majority opinion. Justice Ruth Bader Ginsburg dissented, joined by Justices Stephen G. Breyer, Sonia Sotomayor and Elena Kagan.