A lot can happen in a year, but if all things are the same I'd say Casey is a shoe-in. PA is a moderate state and what we have here is a moderate Dem vs an extremist Repub.
Throw in Santorum's latest move to do away with many of the labor laws (that will go over like a lead brick in Pittsburgh) and you have a guy who seems to want to lose and lose badly.
let's not get ahead of ourselves -i don't want to see the Pennsylvania Democratic Party get so complacent with expectations of a Casey win that they sleep while Santorum works like a busy little bee (and i choose this metaphor from the the movie 'Gladiator' purposefully) in getting support for his reelection bid. let us assume that Santorum has the edge as the incumbent, and that Casey is the underdog with a very real chance of losing, and fight like hell to win, rather than expecting the seat to fall into our laps. because i fully expect that Republicans will work furiously and laboriously to ensure thet Santorum wins a second term -therefore let us not sleep at the wheel.