The former Pennsylvania senator told the Post earlier this week that he is shooting for a top-five finish in the Ames Straw Poll on Saturday.

More realistically, he probably needs a top-three or –fourth-place — finish to be considered a legitimate Iowa contender.

That means, at Tuesday night’s debate, Santorum needs to reclaim some of the conservatives who may have migrated to Rep. Michele Bachmann (R-Minn.). The best thing that could happen for Santorum at the Iowa debate is for Bachmann to stumble. Santorum, of course, could try to play a role in that by pressing the issue.

Santorum has shown a willingness to take shots at rival presidential contenders, former Massachusetts governor Mitt Romney and former Minnesota governor Tim Pawlenty, but so far, Bachmann hasn’t gotten the same treatment. If that changes, Santorum could reap the benefits and turn in a surprise showing at Saturday’s straw poll.

But going after Bachmann won’t be easy, and Santorum needs to tread lightly.

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