Sen. Claire McCaskill (D-Mo.) faces a tough general-election battle no matter who emerges from the Republican primary.

A new poll shows McCaskill in a dead heat with all three of the Republicans hoping to take her on in November. McCaskill is tied at 43 percent with Missouri Rep. Todd Akin, businessman John Brunner and former state Treasurer Sarah Steelman.

But McCaskill will likely have the fundraising edge. She pulled in $1.4 million in the last three months of 2011, while her opponents' fundraising has been rather anemic. The top haul came from Brunner, but four-fifths of his $1.26 million came from his own pocket.

A good sign for Brunner in the survey from Democratic firm Public Policy Polling is that he has increased his name recognition, although 64 percent in Missouri still don't know who he is.

The polling firm's president, Dean Debnam, said McCaskill is definitely one of the country's most vulnerable incumbents, but that the race is shaping up to be the kind of toss-up race that put McCaskill in office in 2006.

“What’s helping her out is that the Republican candidate field isn’t very strong either," Debnam wrote Wednesday in a polling memo.

The survey of 582 Missouri voters was conducted Jan. 27-29 using automated telephone interviews and had a margin of error of 4.1 percentage points.