Aaron Blake at Washington Post's The Fix blog:

If you didn’t know better, you’d think Rick Santorum enjoys being grilled by protesters.

In fact, he probably does. And he should.

The former Pennsylvania senator has been inundated at his New Hampshire events with questions from unsympathetic voices in recent days, pressing him mostly on gay rights but also on issues like the separation of church and state...

...The questions are generally posed by members of a coterie of young political activists who stake out Santorum’s appearances early in hopes of catching him off-guard with questions on social issues.

It hasn’t worked yet. And in fact, one could argue that this is exactly what Santorum wants.

By debating social issues with what are often not-so-versed young antagonists, Santorum is creating oodles of YouTube clips and conflicts that the media loves to cover. And that footage can probably only help him in a Republican presidential contest.

It’s essentially Chris Christie light (so to speak). Santorum invites the jousting because he knows he can handle it and come out on top – at least in the eyes of the socially conservative voters he relies upon.