I think many of us in the commentariat were hoping we were not going to have to examine the somewhat strange career of Rick Santorum, but alas.
Here is E.J. Dionne's take. And John Gehring's.
And from the archives, an important 2005 profile of Santorum in the Philadelphia City Paper.
What emerges from all these analyses is that Santorum's Catholicism is the most important thing about him, and that Santorum's Catholicism is of that variety we associate with the "faithful remnant - the world is against us" kind of culture warriors whom, I believe, misunderstand the cultural situation of the Church and lack the hopefulness appropriate to the people of God. Everything is dire and dangerous. Every issue, however mundane, is seen as possessed with world-historical significance. These guys give chicken little a good name. I do not see how that sells, but it will be fun to watch.