Colorado Republicans lost a Supreme Court appeal Monday over whether a congressional map favorable to Democrats is permanent until after the next census in 2010.

A fractured court refused to consider replacing that map with a GOP-drafted redistricting plan, a defeat for Republicans who have sought to reopen the boundary-drawing process in several states to protect their control of the House.

The Colorado Supreme Court had ruled last December that Republicans violated the state Constitution by pushing a new map through the Legislature just a year after a judge had redrawn the boundaries. District drawing may be done only once a decade, the court decided.

Justices refused Monday to consider an appeal of that decision. Chief Justice William H. Rehnquist (search) and Justices Antonin Scalia (search) and Clarence Thomas (search) wrote separately to say the court was wrong not to hear the case.

States must redraw congressional districts every 10 years to reflect population shifts. Colorado's redistricting after the 2000 census was handled by a judge because lawmakers were not able to agree on new boundaries.

The dispute began when Republicans took control of the state Legislature and decided in 2003 to draw new congressional districts.

Five of Colorado's seven congressional seats are held by Republicans, but the new map made GOP seats safer from Democratic challenges.

Washington attorney Michael Carvin, representing Republicans in the Supreme Court appeal, had asked the justices if "the people of Colorado are utterly powerless to overturn a lone judge's policy preferences for the next eight years."

Carvin urged justices to revisit election law issues raised in the 2000 Bush v. Gore decision, which effectively called the deadlocked presidential election for George W. Bush.

Attorney General Ken Salazar, a Democrat, warned that the court should not allow "undesirable political instability in Colorado" with repeated do-overs of redistricting that could confuse voters and candidates.

"Colorado's congressional districts may change at the whim of the state legislature, forcing congressional representatives to choose between effectively representing their current constituents and currying the favor of future constituents who will determine their fates in the next election," the attorney general's filing said.

Redistricting has been a difficult subject for the Supreme Court. In April, justices split sharply over what courts can do about partisan gerrymandering. Four justices said the courts should be closed to such cases.

A challenge over Colorado's redistricting has been on hold in federal court pending the outcome of the Supreme Court case.

Besides Colorado, Texas is also a state where Republican lawmakers spearheaded new redistricting. Appeals over that are pending at the Supreme Court.

The case is Colorado General Assembly v. Salazar, 03-1082.