To clarify, how will Rick Santorum choose a running mate if he wins the Republican nomination for President? Conventional wisdom is to choose a running mate to help balance the ticket. For example, in the 2008 Presidential election, the Republicans selected a cranky old man from the southwest and balanced him with a mean spirited woman from the northwest. Okay, that's not a great example but the concept is clear.
Santorum is both a fiscal and social conservative. Their is no room to budge as a fiscal conservative because the less tax crowd is also the "money to run the campaign" crowd. Their appears to be no room to move as a social conservative, either. In severely criticizing the speech of candidate John F. Kennedy on the separation of faith and governance, Santorum has made his own stance on personal faith and public policy clear. I'm not criticizing (at least today) Sen. Santorum on his mix of faith and government, but should he earn the GOP nomination for President he will face a tough choice: Either choose a running mate for balance and compromise his public stance on belief and governing, or choose a running mate that mirrors his beliefs and lose the election.
Many have been faced with a similar dilemma. Compromise on strong (ultimate) principals for gain or maintain strong principles and fail. What would you choose?