Republican efforts to recruit a fourth candidate to take on Sen. Claire McCaskillClaire Conner McCaskillSupreme Court battle could wreak havoc with Biden's 2020 agenda The Hill's Morning Report - Presented by Uber - Jan. 6 commission vote delayed; infrastructure debate lingers into June Missouri Republicans move to block Greitens in key Senate race MORE (D-Mo.) are drawing attention to the weak GOP field, and could help McCaskill in the fall.

Prominent members of the party are asking state auditor Tom Schweich (R) to run, according to a source close to him, and he has filed the paperwork indicating an interest. Eighteen top Missouri Republicans penned a letter to him Thursday urging him to formally enter the race.


"There are no other candidates vying for the Republican nomination that can match your unique experiences and talents,” they wrote.

Their efforts indicate a reluctance to settle for the three Republicans already vying for the nomination. Rep. Todd Akin (R-Mo.), businessman John Brunner and former state Treasurer Sarah Steelman (R) have underwhelmed Missouri Republicans and left many clamoring for a stronger candidate.

Akin expressed frustration that some in the party kept grumbling about the field.

“Anybody who’s worried and thinks the field is weak, they ought to run. It’s easy to potshot from the sidelines,” he told The Hill when asked what he thought of the concerns. “I gave up 12 years of [House] seniority and a safe congressional seat because I thought beating Claire McCaskill was a national priority, and I ran because I didn’t feel the other candidates would be good candidates.”

Republicans look at McCaskill and see what should be their easiest target in 2012. The demographics are tough for a Democrat in Missouri, and McCaskill narrowly won her first term in 2006. Her seat is central to the GOP strategy for flipping the four seats they need for a Senate majority (if President Obama is reelected).

This isn’t the first time Republicans have gone looking for a stronger challenger to the senator. Brunner was drafted into the race for similar reasons, and Rep. Blaine Luetkemeyer (R-Mo.) was also courted.

“Shame on the Republicans if we don’t win the Senate race,” said Neil Ethridge, a former local GOP official who signed onto the letter to Schweich. “If we can’t replace McCaskill in the Senate, it’s hard to believe we can take back control of the majority.”

None of the current contenders has caught fire with primary voters.

Brunner has blanketed the airwaves with a self-funded ad campaign, but has struggled with public speaking. Akin has the advantage of holding federal office already, but has been unable to excite voters, and a number of campaign staffers jumped ship. Steelman, the current front-runner, has struggled mightily with fundraising and is detested by many top Missouri Republicans — especially those in St. Louis.

Both Steelman and Akin have turned to their children to head their campaigns — never a sign of strength.

A hard-fought primary will drain all of the candidates’ campaign coffers, although the GOP-aligned American Crossroads and the National Republican Senatorial Committee have already been spending big bucks against McCaskill and are expected to spend even bigger in the general election against the freshman senator, who has stowed away almost $5 million for her reelection bid.

A more divisive Republican primary that exposes the candidates' vulnerabilities could greatly aid McCaskill, who can sit on the sidelines and focus on positive messages. The state’s late primary — in August — will also leave the nominee scrambling to unite a potentially fractured Republican base and replenish his or her coffers.

“It’s going to work in McCaskill’s favor,” said Peverill Squire, a political scientist at the University of Missouri. “McCaskill has to be delighted to see Republicans soaking up scarce resources on a battle within the party, rather than using them on her.”

The fact that others are thinking about getting in the race only shows how vulnerable McCaskill is, according to Brian Walsh, the communications director for the Senate Republican campaign arm. 

"It speaks volumes about Claire McCaskill's political vulnerability that even at this late juncture other Republicans may be looking at this race," Walsh said. "But while anyone else has the right to step forward, we believe that any of the current Republicans candidates can and will win in November."  

It’s not clear how Schweich’s entrance would affect the already crowded race. Sam Fox, a behind-the-scenes GOP powerhouse, and former Sen. John Danforth (R-Mo.) are backing Schweich. But he, Akin and Brunner are all St. Louis candidates and could split that area’s votes, while Steelman has the stronger pull in the rest of the state.

The best hope for Schweich, a former chief of staff to two U.N. ambassadors and an international law enforcement official, is that his entrance would force one or more of the other candidates to bow out. But every candidate has a compelling reason to stay in.

Akin has already committed to giving up his House seat so he could run for Senate, and the race to replace him is already well under way. Steelman is leading in the polls and has a bone to pick with the state’s GOP establishment; she told The Hill in a statement that the status quo fears her because she follows through when she says she will do something. And Brunner has dropped so much of his own cash into his campaign that there is no turning back.

“The guy’s already spent $2 million on it. There’s no way he’s going anywhere,” said a source close to Brunner.

Meanwhile, both Democrats and some Republicans are questioning whether Schweich would be as strong a candidate as his supporters claim. They point to his reputation for having a thin skin and his support for elements of Obama’s foreign policy as potential vulnerabilities.

“These prominent Republicans are saying their only hope for winning this race is Tom Schweich, and the current field is not able to beat Claire,” said a Democratic strategist in Missouri. “It just shows how the field is incredibly weak and fluid.”