Missouri Rep. William Lacy Clay is heavily favored to win his Democratic primary Tuesday, in a match-up with fellow Democratic Rep. Russ Carnahan that was triggered by redistricting, according to a new SurveyUSA poll.

Clay leads Carnahan 56 percent to 35 percent. The survey of 490 likely Democratic primary voters was conducted August 2-4, and has a 4.5 percent margin of error.

Either candidate would be the overwhelming favorite in the solidly Democratic district.