Amy Klobuchar is overwhelmingly popular and would cruise to reelection at this point pretty much no matter who her Republican opponent was.
Klobuchar's approval rating is 59% with only 29% of voters disapproving of her. She is universally well liked by the Democratic base, sporting an 87/5 approval spread within her own party. Independents also approve of her by a greater than 2:1 margin, 62/29. And although only 26% of Republicans think she's doing a good job that's still a good deal above average for crossover popularity during a time when GOP voters have about as dim a view of Democrats as they possibly could.
Klobuchar leads a quintet of hypothetical Republican challengers by margins ranging anywhere from 10 to 18 points. Her closest competitor is Governor Tim Pawlenty, who she leads 53-43. She gets a whooping 97% of the Democratic vote against him, while Pawlenty benefits from a pretty unified base as well with 92% of the GOP vote. Klobuchar also cleans up with independents against him, leading 55-38.
Pawlenty gets 1% of the Democratic vote against Klobuchar. It makes you wonder how someone who can only pull 1% of the Democratic vote in his own state is going to have enough appeal across party lines nationwide to win a Presidential contest.
Faring next best against Klobuchar and the only one of the Republicans who voters in the state have a positive opinion of is Norm Coleman, who trails 54-40. He does worse than Pawlenty because he gets only 85% of the Republican vote and because he trails by 22 points with independents. Still Coleman's 43/42 favorability spread has to be at least a little bit encouraging to him. The last time PPP looked at Coleman, which was July 2009, his favorability was 38/52. He appears to have recovered a fair amount from the dip his poll numbers took due to the perception that he was a sore loser. That bodes well if he does make another run for office sometime in the future.
Michele Bachmann trails Klobuchar 56-39 and is extremely unpopular with voters in the state. Only 37% have a favorable opinion of her to 51% with an unfavorable one, and her deficit against Klobuchar with independents is a remarkable 26 points. She has basically no appeal beyond the Republican base and as a result it seems unlikely she'll ever have a much higher platform than serving in the House.
Klobuchar also leads Congressman Erik Paulsen 52-34 and Gubernatorial nominee Tom Emmer 56-38. For now it doesn't appear likely this will be a competitive race in 2012.
Full results here