Yet it's the familiarity of the Blunt and Carnahan names that makes them attractive to partisans trying to win a key race in a swing state that Obama lost two years ago by fewer than 4,000 votes out of nearly 3 million cast.
Blunt believes his record of winning elections will draw Tea Party voters. "I don't think this is going to be a year when people try to send a message by throwing away their vote on somebody who can't win," he says.
And Tommy Roberts, the Democratic chairman of St. Charles County, thinks Robin Carnahan's late father, Missouri's former governor, will be a powerful asset. "People here loved Mel Carnahan," Roberts says.
The Carnahans are, in some ways, Missouri's version of the star-crossed Kennedys. Robin Carnahan is a breast cancer survivor who lost her father and a brother, Randy, in a 2000 plane crash when Mel Carnahan was campaigning for the Senate. Carnahan won the race anyway, and his wife, Jean, was appointed to serve in his place. She lost an election for the rest of his term.
The Blunts resemble the Bush dynasty: Patriarch Leroy Blunt served as a GOP state legislator from 1978 to 1984. His son, Roy, won three elections as Greene County clerk before becoming Missouri's first GOP secretary of State in more than a half-century and has been in Congress since 1997. The congressman's son, Matt, followed his grandfather into the Missouri House and his father into the secretary of State's office before winning election as Missouri's governor in 2004. He did not seek re-election in 2008.
Both Roy Blunt and Robin Carnahan have almost 100% name identification in the state, according to a Mason-Dixon survey. Both have amassed big war chests: Blunt has raised $8.2 million, compared with $7.3 million for Carnahan, according to campaign-finance records.
Small wonder, then, that GOP leaders, from retiring Missouri Sen. Kit Bond to Rep. Michele Bachmann, a Minnesota lawmaker and Tea Party favorite, are backing Blunt. Or that Obama already has visited to raise money for Carnahan.
An endorsement Blunt got from Missouri state Treasurer Sarah Steelman helped persuade Lucas Case to back the GOP congressman. And so, another political dynasty proved its influence: Steelman is the wife and daughter-in-law of two former Missouri House GOP leaders.
"I have a lot of respect for the Steelman family," Case says.