Daniel Doherty

Is this the beginning of the end for Senator Claire McCaskill? National Journal reports:

Sen. Claire McCaskill (D-Mo.) trails all three of her potential Republican rivals, according to a new survey conducted for two Missouri news outlets, cementing her status as this cycle's most vulnerable incumbent.

Businessman John Brunner (R) holds the largest advantage over McCaskill, leading by a 52 perent to 41 percent margin. Former state Treasurer Sarah Steelman (R) leads by a 49 percent to 41 percent margin. And Rep. Todd Akin (R) leads by a 49 percent to 44 percent margin.

McCaskill's big problems come among independent voters. She scores just 40 percent among independents against Akin, and she's mired in the mid-30s when she's matched up with Brunner and Steelman. And while McCaskill has said she would like President Obama to campaign with her, Obama wouldn't be much of an advantage -- the poll shows Obama trails Mitt Romney by a 51 percent to 42 percent margin.

The poll shows Brunner leading the Republican primary with 33 percent, compared with Steelman at 27 percent, Akin at 17 percent and five other candidates lagging far behind. Though this is his first run for office against two long-time elected officials, Brunner has bolstered his name recognition by spending millions on advertising introducing himself to Missouri voters.

Mason-Dixon Polling & Research polled 625 likely Missouri voters between July 23 and 25 for the St. Louis Post-Dispatch and News 4. The poll has a 4-point margin of error, meaning the Brunner's and Steelman's leads over McCaskill are statistically significant. The poll surveyed oversamples of 400 Republican and Democratic primary voters, each of which carry a 5 percent margin of error.

What's more, just like President Obama, the Senator’s personal favorability rating has also taken a hit:

McCaskill's biggest asset -- her personal favorability -- isn't as big as she may have hoped. Just 37 percent of Missouri voters have a favorable impression of the first-term Democrat, while 44 percent see her unfavorably.

All three Republicans have lower favorable ratings as they build their name recognition, giving McCaskill the opportunity to boost their negatives. And she's trying -- McCaskill has debuted negative ads against all three candidates (Though her ad against Akin looks more like a positive spot aimed at boosting him in the Republican primary).

Not all is lost for Missouri Democrats, though: The poll shows Gov. Jay Nixon is in position to win a second term this fall. Nixon would take 48 percent of the vote against businessman Dave Spence, the poll shows. Nixon holds a huge 52 percent to 31 percent margin among independent voters. Spence has a big advantage in the Republican primary, the poll shows.

McCaskill was one of the first Democratic leaders in the Senate to publicly endorse then-Senator Barack Obama for president in 2007. Now, as it turns out, she won’t even be attending the 2012 Democratic National Convention. (We certainly didn’t see this coming five years ago). And sure, while this may indeed be a “savvy political maneuver” for obvious reasons, I think it underscores a larger point -- namely, any political association with this president is the surest way to lose re-election if you're a vulnerable Democrat in a swing state.

By the way, my friends, don’t expect Senator McCaskill and President Obama to hold any joint campaign events this fall. Oh how the times have changed.


Daniel Doherty

Daniel Doherty is Townhall's Deputy News Editor. Follow him on Twitter @danpdoherty.

Author Photo credit: Jensen Sutta Photography