If his convention strategy is to first deny Romney the nomination... he should share this fact with supporters and play the Sarah Palin card.... “If I was a voter in [state] and I wanted to deny the father of gay marriage and ObamaCare the Republican nomination, I would vote for Rick Santorum.”
That would be tantamount to exiting the race.
Santorum will not get over 57% of Newt supporters. If he can't get within 2% of Romney with Newt in the race, Newt's exit wouldn't help him beat Romney in delegates.
In actuality, Santorum benefits because Romney pulling 4-5 Newt supporters could put Mitt over 50% in some states, denying Santorum all delegates in states where that's a rule.
This is the hard math.