Santorum said Alito would not be a Justice if it weren’t for Specter. Specter was very effective at being the head of the Judicial Committee.
Rick Santorum realized that the Dems would have control of the Judicial Committee, if the GOP didn’t have the majority in the Senate, and he thought Specter would have the best chance of winning, as well as being an effective head of the Judicial Committee.
There was an agreement between Specter and Santorum in that Arlen would vote for good judges in exchange for Santorum’s support.
His word was good.