That is a silly argument, because Newt is pro-life, so I doubt the Santorum support comes from single-issue votes. And given prior pro-life endorsements, I don’t think most pro-lifers are voting single-issue based on the 3 possible winners of the nomination at this point.
Judges will be a big issue, but again, I don’t think pro-lifers are thinking that Santorum or Gingrich would be that different on judges. By the record, Santorum has approved pro-choice judges, Newt hasn’t (because he was never in that position).
On the other hand, while I don’t know Santorum’s endorsement history, I know Newt endorsed at least one pro-abortion candidate, Dede Scozzafosa, over a pro-life candidate, simply because the pro-abortion candidate was the “republican”.
Every candidate on our side would be an improvement over the current occupant on the pro-life issue.
Social conservatives are voting for him because they feel he is stronger on the issue then Newt.