Of Mittens and Santorum who would be the easiest for Dems to defeat?

[Proud Liberal Dem]

4. The fact that GOP isn't sold on either one of them at the moment

suggests that either would be fairly easy. Mitt is the more "establishment" and "mainstream" GOP candidate, so he stands the *best* shot at attracting moderates/independents but he generates almost no real enthusiasm within the GOP base, so he would likely be unable to win the GE and would be huge drag on the downticket races. Santorum would fire up the shock troops on the right though his views would be considered much too far outside the mainstream to actually win the GE. A Santorum candidacy would also increase Dem turnout, which is also going to hurt the GOP. I guess Santorum would be the "easiest" GE nominee to beat. I keep wondering if Romney and Santorum might join forces at some point?