In a ruling that may help Rep. Russ Carnahan (D), the Missouri Supreme Court has asked a lower court to determine whether the state’s new Congressional map complies with the state constitution.

Carnahan saw his Congressional district essentially eliminated in the redistricting process and faces the prospect of either running in a Republican district or challenging a fellow incumbent Democrat.

Missouri was one of the first states to draw a new map, with the Legislature overriding a gubernatorial veto to approve it in May. With the state losing a seat because of population declines, Carnahan was drawn into the 1st district, currently represented by Rep. William Lacy Clay (D). A state circuit court dismissed two lawsuits challenging the new map on the grounds that the lines — in particular the Republican-leaning 3rd district and the safely Democratic 5th district held by Rep. Emanuel Cleaver — did not meet the state constitution’s requirement that districts be as “compact” as practicable.

But the state Supreme Court ruled today that “it was error” for the lower court to throw out those cases. In its opinion, the high court ordered the circuit court to hold a hearing to determine whether “the districts were drawn as compact as may be.”

The circuit court was ordered to enter a judgment on the matter by Feb. 3 so that the Legislature could, in a timely fashion, “redistrict the state, if necessary.” The filing deadline for Missouri is March 27.

“This decision by the Missouri Supreme Court is good news for voters in Missouri, who deserve fair representation,” Carnahan said in a statement. “The Court has sent a clear signal that this lawsuit, brought on behalf of Missouri voters, has merit and deserves to be heard.”

A voice mail left with Cleaver’s office was not returned this evening.