The Santorum Challenge

After all, Gingrich was a known quantity to many Republicans, who couldn't get past the heavy baggage he carried.  And it was easy to know how to take Gingrich on: Make sure everyone remembered the heavy baggage he carries, showcase his ideological and temperamental inconsistencies, and wait for him to spout off and create self-immolating controversy.  Known as a brawler himself, Gingrich couldn't get much traction with his efforts to convince voters that he was being "Romney-boated."

Just as the Gingrich insurgency improved the Romney candidacy, the Santorum candidacy holds the same opportunity -- but with the upside comes greater peril.  Whether he moves toward the nomination strengthened or decisively weakened (perhaps even to the point of a spectacular flame-out) may in large part be determined by how he responds to Santorum.

First, Romney should make sure to keep his differences with Santorum about the issues -- and only the issues.  Santorum's underdog status and compelling personal story (as laid out in his semi-victory speech last night) means that coming after him in anything but the most impersonal and abstract way is going to seem like a form of bullying that won't endear Romney to voters he'll need if he wins the nomination.

Second, even as he makes his policy differences with Santorum clear, let's hope Romney understands that Santorum brings with him some degree of blue-collar cred -- which once helped him win statewide in Pennsylvania, and which which could be very helpful to Romney in the fall should Santorum be willing to stump for him (assuming he wins the nomination).  If Romney comes across at all elitist or condescending as he outlines his economic policy differences with Santorum, he'll simply be softening himself up for the "Wall Street" class warfare attacks that President Obama is planning to launch.

Third, there are the social issues.  We know Romney and Santorum have some differences here -- and that Romney would be considered the more moderate of the two.  In the wake of Santorum's near-win, the press is going to start scrutinizing him, and will report on Santorum's socially conservative stances in a way that's designed to make them sound out of the mainstream.  They will, in essence, invite Romney to participate in this practice -- but he'll do so at his peril.  His reaction will determine whether social conservatives who now distrust him later reach detente in the event he wins the nomination -- or whether their mistrust will harden into active dislike.  Romney needs to remember that the press' implicit invitation to him to join them in their disdain for Santorum means he will be "in" with them until his opponent is President Obama.  Then they'll start treating HIM like the crazy.