U.S. Rep. Roy Blunt (left)  may be from southwest Missouri, but he apparently believes the fate of his Republican bid for the U.S. Senate could rest with his performance in St. Louis County.

Blunt, R-Springfield, has set up his statewide campaign headquarters in the county, as part of the state GOP's emphasis on the county this fall.

"Like Bill Corrigan, I am tired of Republicans losing St. Louis County," Blunt said Saturday night, touching off applause from about 300 attending county Republicans' annual Lincoln-Reagan Dinner in Sunset Hills. Blunt's new state headquarters is about a block away.

Corrigan is a Republican seeking to capture St. Louis County's top post -- county executive -- which has been held by Democrats for almost 20 years. The current occupant is Democrat Charlie Dooley, who is seeking re-election.

U.S. Sen. Christopher "Kit" Bond (left), R-Mo., and the chief honoree at the county GOP's event, emphasized the same point. The county, he said, "is the keystone of this state."

Bond, whose retirement is prompting one of the nation's most closely watched Senate contests in the country, told Saturday's audience, "It's extremely important that you do this job in St. Louis County."

Until the 1990s, Republicans seeking statewide office could usually count on carrying St. Louis County -- the state's largest voting bloc and for decades filled and ruled by suburban Republicans.

But during the past 20 years, formerly city Democrats have moved into the county, while suburban Republicans have moved out to farther flung territory -- St. Charles, Franklin and Lincoln counties among them.

Democrat George "Buzz" Westfall's 1990 victory for county executive, a post he held until his death of a staph infection in 2003, helped solidify his party's hold on county government -- and also signaled the changing political role for St. Louis County.

The county now is increasingly must-win Democratic turf, and often has been the dealmaker in close statewide contests, In 2006, for example, Democrat Claire McCaskill rode to statewide victory on her 51,000-vote edge in St. Louis County. She carried the state by less than 49,000 votes.

Blunt's new statewide headquarters is in a Sunset Hills office building that also houses the new satellite state office for the Missouri Republican Party.

State Republican Party executive director Lloyd Smith introduced the new office's staff to the Lincoln-Reagan Dinner crowd , and added that he now "needs 2,500 volunteers in St. Louis County" to provide the field staff needed to blanket the county over the coming months, leading up to the November election.

Smith contended that a strong Republican showing in the county could mean victory for Blunt, Corrigan and other Republican candidates.

Blunt told Saturday night's crowd that locating his campaign headquarters here underscored his commitment to the area. "Nowhere is going to get more focus in this state than St. Louis County," Blunt said.