Denver ? A battle about a new congressional redistricting law goes to the Colorado Supreme Court today for a ruling expected to be closely watched around the nation.

Over three hours, the justices will hear arguments focusing on the question of just how often the state’s congressional districts can be remapped.

Democratic Atty. Gen. Ken Salazar contends the current plan, written by Republicans, is illegal because the Colorado Constitution calls for redistricting only once every 10 years. Colorado has had two plans in less than two years, one written by a judge, the second by the General Assembly.

A similar once-a-decade argument was raised during Texas’ bitter redistricting fight, although recently Texas Democrats have focused on a claim that GOP redistricting plans would violate the federal voting-rights law.

The Colorado court’s ruling could signal a trend, said political analyst Thomas Mann of the Brookings Institution.

“One bite of the redistricting apple has been the norm for a century, and only if the courts demand revisions do you go back to the drawing board,” Mann said.

“If Colorado and Texas are allowed to stand, I don’t see what’s to stop the process from continuing every election throughout a decade. The idea of relatively permanent, stable districts could vanish,” he said.

Congressional district boundaries must be redrawn after every census to ensure each district has an equal number of residents.

In Colorado, the Democrat-led Senate and Republican-led House failed to agree on new boundaries in 2002, so the task fell to a judge.

Denver District Judge John Coughlin drew a new 7th Congressional District that was nearly evenly divided among Republicans, Democrats and unaffiliated voters.

When the Republicans gained control of the Legislature this year, they approved a map that shifted 27,000 Republicans into the 7th District in Denver’s north and west suburbs. At the same time, they solidified already strong Democratic majorities in other districts.

Salazar filed a lawsuit directly to the Supreme Court, arguing that redrawing districts a second time in a decade violated the state Constitution.

He asked the court to bar Republican Secretary of State Donetta Davidson from enforcing the new districts.

Davidson fired back with her own lawsuit, also being considered during the arguments today, asking the court to rule that Salazar lacked the authority to seek a court order preventing enforcement of the new map.

Davidson also has contended that Salazar violated professional rules of conduct by suing her even though she is his client as a fellow state officer.

Congressional redistricting was a thorny issue for Kansas in 2002, and Lawrence was split between the 2nd and 3rd districts in the final draft.