IA being many of the candidates last hope obviously is no longer feasible and they should probably all drop out within the next two weeks. There is literally zero room for another Santorum to happen. Not even logically possible. Trump AND Cruz can't crash and burn while a candidate storms the state to 30%+ in less than 5 weeks.
Santorum won with 25% in 2012. It's possible, although not likely, that the winner this year could get only 18 or 20 percent.
Not enough room, time, or momentum with Cruz & Donny for a candidate to squeeze out 20% that fast, sadly.
Santorum was only at 3% this far out.
But it's worthy noting there was not nearly the momentum/cram of fanbases at the top. He's not going to break up a Carson base, a Cruz base, and a Trump base and shred them to pieces and magically hit a homerun in the next month. No candidate possibly can. Much, much more difficult than it would be to surge in the socially conservative state in 2012.
