Vice President Joe Biden vowed the administration will do “everything in our power” to ensure equal voting practices after the Supreme Court struck down a section of the Voting Rights Act. (The Washington Post)

In calling for a rewrite of one of the nation’s most significant civil rights laws , the Supreme Court has demanded that the other two branches of government design a guarantee of racial equality that reflects the realities of the 21st century.

But the real question is whether the political system, broken and polarized as it is, still has the capacity to take on such a challenge.

The ruling, which said Congress must update the Voting Rights Act of 1965, noted that much has changed for the better since the original formulas were written requiring federal approval of even minor ­changes in election procedure for some states and jurisdictions.

But the court also acknowledged that discrimination still exists and that rectifying it demands vigilance from Washington.

Traditionally, voting rights is an area where presidents and lawmakers, mindful of history’s judgment, have proven capable of working together across party lines.

The most recent reauthorizations of the Voting Rights Act were signed by Republican presidents, Ronald Reagan and George W. Bush. In 2006, not a single senator voted against the current version, while fewer than three dozen members of the House did.

“Members of both parties have not wanted to break the social contract we made,” said Sherrilyn Ifill, president and director-counsel of the NAACP Legal Defense and Educational Fund. “I really believe this Congress will not want to break that compact.”

Seven years later, though, the political landscape is more divided and Congress more gridlocked.

“If the five justices who voted to gut this landmark legislation think that this Congress has the ability to reform this legislation in the current hyper-partisan environment, they are beyond naive,” said Ronnie Musgrove, a former Democratic governor of Mississippi.

Adding to the difficulty — and sensitivity — is the fact that any new formula for determining which jurisdictions merit “preclearance” from the Justice Department is likely to bring in states and localities never previously included in the act.

“That’s going to [make it] hard for Congress to meet the challenge the chief justice has laid down,” said Charles Bullock, a political science professor at the University of Georgia and author of a book about the Voting Rights Act.

Electoral calculation will inevitably find its way into any endeavor to rewrite the law.

For instance, Congressional Black Caucus members Rep. Marcia L. Fudge (D-Ohio) and Rep. James E. Clyburn (D-S.C.) agreed that the Voting Rights Act needs reworking — but they mentioned their desire to see it expanded into Ohio and Pennsylvania. Those are two big battleground states that tried to change voting laws during last year’s presidential contest.

President Obama called upon Congress to act, and in the Democratic-led Senate, Judiciary Committee Chairman Patrick J. Leahy (D-Vt.) vowed to hold hearings next month to begin the process.

Leahy called the court’s 5 to 4 decision a “stunning reversal” and said that given “five justices who decided they know a lot better than the hundreds of others who’ve worked on this — I think we then come back with an answer.”

But his counterpart in the Republican-controlled House, Judiciary Committee Chairman Bob Goodlatte (R-Va.), mentioned no such imperative for action.

“The Supreme Court has now decided [the current] formula does not meet constitutional requirements,” Goodlatte said. “This decision in no way affects the permanent, nationwide ban on racial discrimination in voting found in Section 2 of the Voting Rights Act, which remains in place.”

House Speaker John A. Boehner (R-Ohio) declined to comment on the court’s ruling; his office instead referred inquiries to the Judiciary and House Administration panels.

Yet partisan and ideological battle lines had formed within hours of the ruling.

“As long as Republicans have a majority in the House and Democrats don’t have 60 votes in the Senate, there will be no preclearance,” said Sen. Charles E. Schumer (D-N.Y.).

Meanwhile, Republicans hailed the decision as putting the brakes on what they view as overzealous actions on the part of the Obama administration in blocking states’ ability to regulate their own election processes.

“No longer will any Justice Department be able to misuse the Voting Rights Act concerning such common-sense measures as voter identification laws,” said Sen. Charles E. Grassley (R-Iowa), the ranking Republican on the Senate Judiciary Committee.

Grassley did, however, describe himself as “open to looking at ways to address the issues addressed in the court’s decision.”

A failure or refusal to act is not without political risk, particularly if it encourages state and local governments to enact new provisions that tamp down minority voting.

“What we saw in 2012 was that a systematic attempt to suppress voters can rebound against the suppressors,” said former Obama campaign manager Jim Messina.

Although Republicans would disagree with Messina’s characterization of their intent, Obama strategists say the fear was great enough among young and minority voters that it encouraged them to make an extra effort to get to the polls. That paid off for the president’s reelection effort in such crucial battlegrounds as Florida and Ohio, they said.

“Some people want to say that the election of President Barack Obama is a fulfillment of Dr. King’s dream. I say no, it’s a down payment. We are not there yet. Racism is still deeply embedded in every corner and of every fiber of our society,” said Rep. John Lewis (D-Ga.), a revered figure of the civil rights movement.

Meanwhile, areas of the country subjected to federal scrutiny under the act say they have been unfairly stigmatized, rather than given credit for the gains they have made toward equality.

“Our data today is better than a lot of people who are not subject to Section 5 of the Voting Rights Act,” said former Mississippi governor Haley Barbour, a Republican.

Some predict, however, that the vacuum created by the court’s decision will create opportunities to roll back those gains — especially in low-profile, local elections, which often go below the national radar and where experts say the Civil Rights Act has had its greatest impact.

“The creativity of discrimination is fairly infinite when you don’t have a referee or a judge to make sure you play fair,” said Don Fowler, a South Carolinian and former chairman of the Democratic National Committee. “I view this as a really damaging blow to the sense of fairness and integrity in Southern states. I just think it opens the door to turn the clock way back.”

Ed O’Keefe contributed to this report.