JEFFERSON CITY - A decision by U.S. Rep. Russ Carnahan, D-St. Louis, to challenge U.S. Rep. William Lacy Clay, D-St. Louis, for a congressional seat has left Democratic lawmakers hoping a primary between the two can be avoided with a Missouri court decision.

As candidate filing began Tuesday, Carnahan and Clay filed for the same congressional district, which includes all of St. Louis City and northern St. Louis County.

The Missouri Supreme Court is expected to rule within days on a legal challenge to the new congressional maps passed by the General Assembly after overriding a veto from Democratic Gov. Jay Nixon.  

"We are still hopeful that the Supreme Court and this body will end up revisiting the maps, and we'll be able to work that out, because I would hate to see them run against each other," said Rep. Susan Carlson, D-Saint Louis City.

Rep. Tishaura Jones, D-St. Louis City, says the contest will not be pretty and will be divided along racial lines.

"This is going to be a very divisive race, for the city and for the region," Jones said, "It's going to be hard, its going to be nasty, its going to be ugly, everything that people don't like about politics, this race is going to embody that."

The new district Carnahan and Clay are fighting for has an almost 50 percent minority population. Clay has held the majority of the new district since he took office in 2001. His father and co-founder of the Congressional Black Caucus, Bill Clay, held the same seat starting in 1969.

Carnahan was first elected to Congress in 2005 in the district long held by former U.S. House Minority Leader Democratic Rep. Dick Gephardt.

Jones said race will play a huge role in the primary, but she is supporting Clay.

"Even though some may think we are in an era of post-racial politics, race is still an issue, and its an ever-present issue when it comes to this race. Blood is thicker than water, and I have a long standing familial relationship with the Clay family, so I have to go where my family goes, in this instance," said Jones.

Rep. Mike Colona, D-St. Louis City, says he isn't surprised by Carnahan's decision.  

"Some people may look at Carnahan filing in the first district more as a place-holding move," said Colona, "we were hoping to avoid a Democratic Primary in the first, but if the courts don't come out with new maps, it looks like that is what's going to happen."

The August Primary is slated for August 7. Candidates have until March 27 to file for office.