Missouri Sen. McCaskill trails Republican challengers in new poll

Regardless of who wins the Aug. 7 Republican primary to take on Democratic Sen. Claire McCaskill, the Missouri senator polls far behind her opponent, according to a new survey (PDF) released this weekend.

McCaskill trails businessman John Brunner 52 to 41 percent, former state treasurer Sarah Steelman 49 to 41 percent, and Rep. Todd Akin 49 to 44 percent among likely voters surveyed July 23-25 by Mason-Dixon polling for the St. Louis Post-Dispatch and News 4. Brunner leads the race for his party's nomination. The poll's margin of error was plus or minus 4 percentage points.

McCaskill's seat had early been marked as a potential Republican takeover due in part to the state's competitive demographics. Obama lost Missouri in 2008 by less than 4,000 votes, but this cycle, both parties regard Missouri as Romney territory rather than a swing state.

Respondents to the Mason-Dixon poll handed President Barack Obama a high unfavorable rating of 51 percent with a 34 percent favorable rating. Mitt Romney received a 27 percent unfavorable and a 39 percent favorable rating among likely voters surveyed.

Vice President Joe Biden campaigned for McCaskill in her home state earlier this month.