(CNN) -- Arizona has become the latest jurisdiction to challenge continuing federal oversight over a key provision of the landmark Civil Rights Act of 1965. Officials in Phoenix filed a lawsuit in federal court Thursday, saying requirements to preclear all local voting changes with the U.S. Justice Department are unconstitutional.
It follows a Supreme Court ruling two years ago that gave states and local communities more power to appeal the preclearance provision of the law. That section provides continuing federal control over election practices in 16 states, based on past discrimination against minority voters. Other states are not covered by the provision even if they, too, might discriminate against minority voters.
The conservative high court majority ruled the Justice Department was applying the powerful enforcement tool too broadly.
Arizona Attorney General Tom Horne said Washington punishes states with "random enforcement based on the whim of federal authorities."
"Arizona has been subjected to enforcement actions for problems that were either corrected nearly 40 years ago and have not been repeated, or penalized for alleged violations that have no basis in the Constitution," Horne said. "That needs to stop."
At issue is whether Congress in 2006 properly extended the civil rights law -- whose Section 5 mandates that the covered states get advance approval of changes in how their elections are conducted -- or whether the country has made enough progress on racial equality to make continued federal oversight essentially unnecessary.
The high court concluded in its narrow ruling that sufficient progress had been made.
Under the law, "things have changed in the South. Voter turnout and registration rates now approach parity," wrote Chief Justice John Roberts. "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."
But while opening the door for challenges to the law, the court upheld the federal government's enforcement power. And it refused to resolve the larger constitutional questions of when race-based solutions can be used to remedy past and present voter discrimination.
With this legal challenge from Arizona, the conservative majority may be poised to tackle the issue in coming years. But first, a federal judge will handle the state's lawsuit. No trial has yet been scheduled.
Attorney General Eric Holder vowed to defend the law in court.
"The Voting Rights Act plays a vital role in our society by ensuring that every American has the right to vote and to have that vote counted," Holder said in a prepared statement. "The Department of Justice will vigorously defend the constitutionality of the Voting Rights Act in this case, as it has done successfully in the past. The provisions challenged in this case, including the preclearance requirement, were reauthorized by Congress in 2006 with overwhelming and bipartisan support."
The 2009 high court case involved a small homeowners association board outside Austin, Texas. Residents of the Canyon Creek planned community eight years ago sought to move its federal-election polling place to an elementary school that is the neighborhood's polling place for all other elections. Such a move required federal approval under Section 5, which was eventually granted.
Backed by a group of conservative activists, residents launched a direct challenge to the law's "preclearance" provision, arguing it should not be enforced in areas where it can be argued racial discrimination no longer exists. The high court's ruling made the Texas district eligible to "bail out," or become exempt from future federal oversight.
Civil rights groups say Section 5 has proven an important tool to protect minority voters from local governments that could set unfair or unconstitutional barriers to the polls. If it were to be ruled unconstitutional someday, they argue, the very power and effect of the entire Voting Rights Act would crumble.
Since 1982, only 17 jurisdictions have been able to "bail out" or become exempt from federal oversight, out of about 12,000 covered political jurisdictions.
Arizona has also challenged Washington's authority to enforce immigration laws. A state measure known as SB 1070 would, among other things, give local law enforcement agencies the power to apprehend and help deport illegal immigrants. The Obama administration say immigration is the exclusive role of the federal government.
The civil rights case is State of Arizona v. Holder.