The Hotline's Julie Sobel writes:
Former Missouri Sen. Jim Talent (R) told the St. Louis Post-Dispatch Thursday that he will not challenge Sen. Claire McCaskill (D-Mo.) in 2012. Talent, originally thought to be a likely contender in the race, has in recent weeks sparked widespread speculation that he would pass on a bid. Now that he's making it official, the Republican primary field is expected to expand quickly. [...]
Former Treasurer Sarah Steelman (R) is currently the only Republican in the Senate race, but Talent's exit makes the possibility of a large, contentious Republican primary more likely. Republican National Committee chair candidate Ann Wagner (R) has said she is considering the race, and that she wouldn't run if Talent decided to get in. Rep. Jo Ann Emerson (R) is considering a run for the Senate as well and her verdict will also be motivated by Talent's decision.
Other Missouri Republicans who've said they are considering the race include Rep. Sam Graves (R) and 2010 congressional candidate Ed Martin (R).