A federal judge on Wednesday questioned whether a key component of the landmark Voting Rights Act is outdated, expressing skepticism about using evidence of racial discrimination from 40 or 50 years ago to justify continued election monitoring for a group of mostly Southern states.

U.S. District Judge John Bates' comments came during oral arguments in an Alabama county's lawsuit targeting the law — a constitutional challenge that a number of legal observers predict could well reach the Supreme Court.

Shelby County, backed by conservative legal groups, maintains that it and other covered state, county and local governments should no longer be forced to get federal approval before changing even minor election procedures. They note that the Voting Rights Act — enacted in 1965 and extended by Congress for another 25 years in 2006 — relies heavily on past discrimination in determining which jurisdictions are covered by the "pre-clearance" requirement for election changes, such as moving a polling place or redrawing school district lines.

Bates posed sharp questions to the legal teams on both sides but at times appeared sympathetic to the county's argument.