Rep. Roy Blunt (R-Mo.) is set to announce Thursday that he will run to succeed retiring Sen. Kit Bond (R-Mo.) next year.
Blunt is expected to make the announcement at 9:30 a.m. in St. Louis, according to knowledgeable sources.
The former House Minority Whip is considered the favored nominee of Republican insiders in Washington, D.C., and Missouri. His strong fundraising base and political network will be major assets for him in a statewide run. Still, he could face a primary against former state Treasurer Sarah Steelman (R), who lost a GOP primary bid for governor last year.
Blunts son, Matt, is a former governor of Missouri who decided not to seek re-election in 2008.
Missouri Secretary of State Robin Carnahan (D) has already announced her Senate bid, and the contest is expected to be one of the most hotly contested of the 2010 election cycle.
Republicans lost the other Missouri Senate seat in 2006, when now-Sen. Claire McCaskill (D-Mo.) defeated then-Sen. Jim Talent (R-Mo.).