Rep. Michele Bachmann's trip to Iowa and rumblings about a presidential bid were enough for one polling firm to put her up against President Obama as its "monthly wild-card pick" in a hypothetical 2012 match-up, but she trails Obama by 18 points, the polling firm said Thursday.

Public Policy Polling found that Obama beat Bachmann 51-33, with 17 percent undecided. Bachmann's favorable rating in the nationwide survey was 22 percent favorable, 31 percent unfavorable, and 48 percent not sure.

The poll found Obama also leads the four 2012 GOP frontrunners, beating former Massachusetts Gov. Mitt Romney and former Arkansas Gov. Mike Huckabee by 5 points, former House Speaker Newt Gingrich by 11 points, and former Alaska Gov. Sarah Pain by 17 points.

Former Gov. Tim Pawlenty was not included in the survey.

The latest figures are an improvement for Obama against all four potential Republican challengers compared to the firm's poll taken a few weeks after the 2010 election.