The Supreme Court agreed Monday to referee a congressional boundary dispute from Mississippi, a victory for Democrats who are contesting a plan that helps Republicans.
The case will be the first reviewed by the court over boundaries drawn using 2000 census data. Plans by many other states are also being contested.
The court did not intervene in time to affect this year's election, however. Primaries were held last week in districts favorable to Republicans approved by a federal panel earlier this year.
Mississippi is losing one of its five congressional seats because of sluggish population growth in the 1990s, and incumbents Chip Pickering and Ronnie Shows are competing for one seat.
The ultimate question is which court-drawn plan becomes Mississippi's map, one that favors the Republican drawn by a federal three-judge panel or a state judge's plan that would make it easier for a Democrat like Shows to win.
The federal panel ruled that the state judge didn't have a constitutional right to get involved in this congressional redistricting challenge.
Robert McDuff, the lawyer for a group of Democrats, told the Supreme Court that the ruling "if affirmed, will leave congressional redistricting disputes almost entirely to the federal courts.''
He said in the past year state courts around the country have been involved in redistricting fights, including courts in Colorado, Minnesota, New Mexico, Oregon, and Texas.
The Republicans' attorney, Michael B. Wallace, said framers of the Constitution would have been "astounded'' to see a state court with power over federal elections.
He said if state judges had that authority, some legislators may refuse to draw new maps and "choose instead to seek political results from selected state judges.''
Every 10 years states must redraw boundaries for congressional and legislative districts to reflect population shifts found in the census. Mississippi's redistricting took a messy turn last year when competing plans split the Democrat-controlled Legislature. That left the boundary-drawing to the courts.
A group of Democrats asked a state judge to settle the matter. Republicans went to federal court.
The dispute has been high profile because Mississippi is one of four states where incumbents of opposite parties are vying for the same seat. The others are Connecticut, Illinois and Pennsylvania, with some states still working on plans.
The Supreme Court will hear arguments in the term that begins next fall in the Mississippi case.
Mississippi's case is more complicated because the Justice Department oversees state elections to ensure fairness to minorities, a requirement because of the state's history of racial oppression.
Democrats had accused the Bush administration and the Justice Department of playing political games with Mississippi redistricting by delaying consideration of the state court plan. The Justice Department said because the plan was blocked by a federal court, it was not valid.
In Mississippi, there was little doubt that the central Mississippi districts of Pickering and Shows would be combined. At issue was how.
Lawyers for both sides used the Supreme Court's 2000 ruling in Bush v. Gore to bolster their arguments in filings with the high court.
The court has heard arguments in one other case that would affect congressional elections, and potentially the makeup of the House.