when they feel it is too late for Ron Paul to run third party (not that he would). Santorum will drop out before the convention because he is a team player. The real question is how many delegates does he really have once released. I expect he has enough to push Romney over the top but I hope not!
That said, a lot can change over time and there is still time. RP folks need to take over all the delegate spots especially those we expect to drop out (Santorum). ewwww, what a horrible job. Buy your sweater vest now.