Washington (CNN) -- A divided federal appeals court in Washington has upheld a key enforcement provision of the landmark Voting Rights Act of 1965.
Known as Section 5, it gives the federal government open-ended oversight of states and localities with a history of voter discrimination. Any changes in voting laws and procedures in the covered states must be "pre-cleared" with Washington.
The provision was reauthorized in 2006 for another quarter-century, and an Alabama county subsequently filed suit, saying the monitoring was overly burdensome and unwarranted.
But in this case, a majority of the federal judges disagreed.
"Congress drew reasonable conclusions from the extensive evidence it gathered and acted pursuant to the Fourteenth and Fifteenth Amendments, which entrust Congress with ensuring that the right to vote -- surely among the most important guarantees of political liberty in the Constitution -- is not abridged on account of race," said the 2-1 panel of judges. "In this context, we owe much deference to the considered judgment of the people's elected representatives."
The court took a cautious, somewhat narrow approach, affirming longstanding policies while acknowledging that the conservative Supreme Court majority in recent years has raised concerns over whether "the extraordinary federalism costs imposed by Section 5" -- in the words of the appeals court -- mandate continued oversight.
The ruling comes in a presidential election year that will incorporate newly redrawn voting boundaries, based on the updated census.
State legislatures are charged with creating maps to provide equal representation in state and congressional districts. States covered under Section 5 must have those maps approved by either the Justice Department or a special federal panel.
Various nationwide challenges have been reviewed by the gamut of federal courts. In January, the U.S. Supreme Court ordered a lower court to take another look at the Texas voter map, which had been passed by a Republican legislative majority but challenged by a coalition of Democrats and civil rights groups.
The Alabama dispute is from Shelby County, a largely white suburb of Birmingham. Unlike other jurisdictions, the county never sought a "bailout" or exemption from Section 5 oversight.
Local officials argued that there was no evidence of a "systematic campaign of voting discrimination" in Shelby or any current "defiance" or resistance to ensuring the rights of minorities to vote.
Citing a federal standard, Shelby said continued federal monitoring was "no longer congruent and proportional to the problem (Washington) seeks to cure."
Civil rights groups say Section 5 has proved an important tool to protect minority voters from local governments that could set unfair or unconstitutional barriers to the polls. If it were ruled unconstitutional, they had warned, the very power and effect of the entire Voting Rights Act would crumble.
"The (appeals) court properly found that Congress' decision to maintain Section 5 was grounded in the many instances of recent voting discrimination," said Jon Greenbaum, chief counsel for the Lawyers' Committee, who argued in favor of the law before the federal courts.
There has been much political disagreement over whether Section 5 should continue to stay in place and whether minority voter discrimination remains a nationwide problem, particularly in large parts of the South and Southwest.
Three years ago, the high court found that the powerful enforcement tool in the Voting Rights Act was being applied too broadly in a small Austin, Texas-area municipality. But the high court also suggested -- but never fully affirmed -- that continued use of Section 5 may soon be nullified.
All or parts of 16 states, including Alabama, are currently covered under the provision. Other states are not covered by the provision even if they, too, might discriminate against minority voters.
"Things have changed in the South. Voter turnout and registration rates now approach parity," Chief Justice John Roberts wrote in 2009. "Past success alone, however is not adequate justification to retain the preclearance requirements. The Act imposes current burdens and must be justified by current needs."
Since 1982, only about 20 jurisdictions have been able to "bail out" or become exempt from federal oversight, out of about 12,000 covered political jurisdictions.
"It is unlikely that Congress intended the provision to have such limited effect," Roberts said at the time, in the face of statistics showing voter turnout and registration rates reaching parity between the races in most areas of the country.
Shelby County now has the option of asking the high court to review the case.
The case is Shelby County, AL v. Holder (11-5256).