As Sen. Claire McCaskill braces for a tough re-election bid in 2012, Missouri Republicans are scrambling to figure out who they will put on the ballot against her. What looked like an obvious rematch between the Democrat and former Sen. Jim Talent has turned into a free-for-all on the Republican side since Talent won’t run after all. 

With the swing state losing a House seat through reapportionment, some GOP Members are considering trying for a promotion. But in a continuation of the 2010 tea party surge, candidates affiliated with the movement are eyeing bids and are already criticizing those with “insider” credentials.

The race started to get more crowded Monday when Ed Martin, a former Congressional candidate who helped start the influential St. Louis Tea Party, announced he would run for the seat in an online video. Breaking from other contenders who are conferring privately with colleagues about whether they might run in an effort to avoid intraparty battles, Martin told Roll Call that he made his own decision about the race. 

“I’m not the career politician insider guy, despite having been successful in various ways, so I stopped thinking about whose permission I had to ask,” he said Monday afternoon. Martin said he made about 150 calls related to the race in the two weeks leading up to his announcement but hasn’t been involved in conversations about which candidates might not run if other candidates jump in.

Martin is best known in the state for serving as chief of staff for former Gov. Matt Blunt (R). He ran a close race against Rep. Russ Carnahan (D) last fall.

Senate hopefuls have been eager to take up the tea party mantle, even though, as Martin pointed out, the tea party does not endorse candidates. 

Gina Loudon, a tea party activist who lives west of St. Louis, said she has gotten calls from potential candidates, including at least three whose names haven’t already been mentioned publicly. 

“I don’t think it will be as predictable as the political pundits in the past have thought it would be,” she told Roll Call. 

In the 2010 Senate race, then-Rep. Roy Blunt ran into some problems with tea party activists during his GOP primary bid, drawing protests for his role in helping pass the Wall Street bailout bill in 2008. 

Blunt easily won the primary against state Sen. Chuck Purgason and was victorious in the general election, but some tea partyers still won’t support him publicly. Sara Dickson, an activist who volunteered on behalf of now-Rep. Vicky Hartzler (R-Mo.), wouldn’t tell Roll Call whether she voted for Blunt. Dickson would only say that she “didn’t agree with Roy 100 percent of the time.” 

Democrats are hoping to leverage Republican division for McCaskill’s gain in a repeat of their 2010 strategy trying to exploit intraparty fights. Last year, tea-party-affiliated candidates defeated Republicans preferred by the Washington establishment, upending those races and ultimately costing the GOP several victories.

The remaining potential candidates are trying to sort out among themselves who might be the strongest candidate to face McCaskill in 2012. It’s a tight-knit Missouri Republican crowd. In some cases these potential candidates are either friends or have worked in similar circles, and it’s likely they are taking cues from one another before making final decisions on the Senate race.

McCaskill is one of the most vulnerable Senators up for re-election in 2012, having defeated Talent with just 49.6 percent of the vote in a great year for Democrats. McCaskill’s office declined to comment for this story, and her year-end fundraising totals, due Monday night, were not available at press time.

Former state Treasurer Sarah Steelman last year was the first Republican to announce her candidacy. She initially started running for Senate in 2010 but earned goodwill when she stepped aside for Blunt. Like Martin, Steelman framed her candidacy in a way that would appeal to the tea party, talking about the need to shrink the size of government.

Yet Martin said he’s “not entirely comfortable with some of her public positions” when she was a state legislator, pointing to her support from labor unions and her opposition to tort reform. 

At least three more Republicans are debating whether to join the race: Reps. Sam Graves and Jo Ann Emerson and former Missouri GOP Chairwoman Ann Wagner, who in January lost a bid to be chairwoman of the Republican National Committee. 

Wagner’s credentials could irk tea partyers, given she has served as RNC co-chairwoman, President George W. Bush’s ambassador to Luxembourg and chairwoman of Blunt’s Senate campaign.

All three have been coy about their plans, but Graves said he would make a decision this week. A SurveyUSA poll partially released by Axiom Strategies last week showed Graves to be the strongest candidate against McCaskill.

Another factor affecting the Senate race: Graves now chairs the Small Business Committee, and Emerson is in charge of a subcommittee on the powerful Appropriations Committee.

In the meantime McCaskill shouldn’t breathe easy. Roll Call Politics rates this race a Tossup.