WASHINGTON — The Obama administration and civil rights groups are defending a key section of the landmark voting rights law before the Supreme Court, insisting that reformed state, county, and local governments can use an escape hatch from the law’s strictest provision.
The Voting Rights Act effectively attacked persistent discrimination at the polls by keeping close watch, when it comes to holding elections, on those places with a history of preventing minorities from voting. Any changes, from moving a polling place to redrawing electoral districts, can’t take effect without approval from the Justice Department or federal judges in Washington.
But the Voting Rights Act allows governments that have changed their ways to get out from under this requirement by using a ‘‘bailout provision.’’ Nearly 250 counties and local jurisdictions have done so; thousands more could be eligible based on the absence of recent discriminatory efforts in voting.
The viability of the bailout option could play an outsized role in the Supreme Court’s consideration of the voting rights law’s prior approval provision, although four years ago, conservative Justice Clarence Thomas said the prospect of bailing out had been ‘‘no more than a mirage.’’
The court will hear arguments Wednesday in the case, which is among the term’s most important, in a challenge from Shelby County, Ala.
Opponents of the law say they no longer should be forced to live under oversight from Washington because the country has made enormous racial progress, demonstrated most recently by the reelection of President Obama.
They object in particular to the 40-year-old formula by which some jurisdictions, most in the Deep South, are swept under the law and others remain outside it.
The administration and its allies acknowledge that there has been progress. But they say minority voters still need the protection the law affords from efforts to reduce their influence at the polls. Last year, federal judges in two separate cases blocked Texas from putting in place a voter identification law and congressional redistricting plan because they discriminated against black and Hispanic residents.
Obama talked about the case in a radio interview last week. He told SiriusXM host Joe Madison that if the law were stripped of its advance approval provision, ‘‘it would be hard for us to catch those things up front to make sure that elections are done in an equitable way.’’
Also, the law’s defenders say places that have changed their ways can win release from having to get Washington’s blessing for election changes. Governments seeking to exit have to show that they and the smaller jurisdictions within their borders have had a clean record, no evidence of discrimination in voting, for the past 10 years.
Shelby County has never asked to be freed from the law, but would seem to be ineligible because one city in the county, Calera, defied the voting rights law and prompted intervention by the Bush Justice Department.
Yet places with a long, well-known history of discrimination probably could find their way out from under federal monitoring, according to a prominent voting rights lawyer who used to work for the Justice Department.
The Supreme Court made clear its skepticism about the ongoing need for the law when it heard a similar case in 2009.