The retirement of Rep. Dick Gephardt (search) could clear the way for a candidate with a famous political surname. State Rep. Russ Carnahan (search), the scion of one of Missouri's most famous political families, is viewed as the odds-on favorite to win the Democratic primary Tuesday and go on to victory in November.

For half a century, Missouri's 3rd Congressional District has been a hallmark of constancy.

Since 1953, only two people have held the seat: Rep. Leonor K. Sullivan and Gephardt, who was elected to the first of 14 terms in 1976 and went on to become the House Democratic leader and a presidential candidate on two occasions.

"It's all over," said Ken Warren, a pollster and Saint Louis University political science professor. "There's a lot of money on Carnahan. I don't see how he can lose. He's ahead 20 points."

That hasn't stopped the race from turning nasty in the past two weeks. Some competitors and even constituents have attacked Carnahan's attendance and record in the Legislature and called him the least qualified of the nine Democratic contenders. Carnahan, in turn, says his rivals are misrepresenting his record and trying to hurt his good name.

Carnahan is in his fourth year as legislator but has spent a lifetime in a highly visible Missouri political family. He is the son of the late Gov. Mel Carnahan and former U.S. Sen. Jean Carnahan, and the grandson of A.S.J. Carnahan, a former congressman and the first U.S. ambassador to Sierra Leone.

He called this moment a "historic turnover" in the district and bristled at claims he was not up to the job. He said he is not running on the family name but will earn his stature in Congress "the old-fashioned way."

Warren cited a poll from April that had Carnahan ahead with 38 percent of the vote. His next-nearest competitor, state Sen. Steve Stoll, has 15 percent. The poll is three months old, but "it still means something," because few candidates can afford TV advertising to get their message out, Warren said.

Warren said Carnahan's campaign chest and name recognition are an unbeatable combination. Because voters are largely unaware of the candidates and their issues, most will vote the name they are comfortable with, Warren said.

Nine Democrats are in the race, including university lecturer Jeff Smith, who helped direct Bill Bradley's 2000 presidential campaign in Iowa, and who has been endorsed by former presidential contender Howard Dean (search). He is running a strong grass roots campaign and a packed schedule that includes a bike trek through the district. Former state Reps. Joan Barry and Jo Ann Karll are also running.

Two Republicans will face off in the primary, including Bill Federer (search), who lost to Gephardt in 1998 and 2000. Federer's endorsements include celebrities Pat Boone, Chuck Norris, and Art Linkletter, and former U.S. Attorney General Edwin Meese.

But the Republican nominee will face long odds in November. The GOP has not held the seat since 1949 and has represented the district for only 24 of the past 157 years.