I agree...this might have worked right at the Florida primary time but now it’s nothing.
I think the *only* way to stop Romney is Santorum/Gingrich, or Gingrich/Santorum, with the former being much more likely.
I share your concern, and think that Romney will likely get more delegates than Santorum or Gingrich. However, it also seems quite possible that Santorum + Gingrich will get in the neighborhood of 1,300 delegates, sufficient to deprive Romney of a 1,144 delegate majority.
Which means a contested convention.
Which means...I don’t know what happens after that, but Romney is by no means a lock in a convention in which a significant majority of delegates represent voters who pulled the lever against him.
(And that’s one argument against Gingrich-Perry. A Gingrich-Santorum or Santorum-Gingrich ticket might unite their respective factions at the convention, so as to prevail over Romney on a 2nd ballot.)