A brokered convention that benefits is unlikely because a Santorum strong enough to take states off Romney is strong enought to take even more off Newt.
You’d have to see something like this:
Santorum (18)
MN, IA, MO, CO
KY, IN, OH, PA
WA, ID, MT, ND
SD, KA, NE, OK
TX, WV
Newt (8)
GA, SC, AL, MS, LA, AR, TN, NC
Even here- Newt doesn’t have enough to swing the brokered convention in his favor vs Santorum. To do this, Newt would need to win states like TX + OK + WV + KY (bringing him up to 12), and Santorum down to 14.
If Santorum doesn’t do as well in the North, not only does Newt fail to force a brokered convention - Romney wins the nomination outright.
You don’t seem to be accounting for the fact that most states are not winner-take-all. It takes a whole lot more calculating to do the delegate math than you’re doing. You’re also making the strange assumption that Santorum and Newt’s standings in the polls are going to stay static. That’s highly unlikely. Santorum had his chance and blew it in a big way. His momentum is gone. The voting on the last day swung against Santorum. In fact, Newt got a BIG bump in the last-day voting, indicating major Newtmentum:
http://www.cnn.com/election/2012/primaries/epolls/mi?hpt=hp_t1
Newt got 11% of the last-minute vote. He only got 3% in the few days before that, and only 8-6-7% in the months before that. So Newt had way more support in Michigan on Monday than his average before in the entire campaign. Santorum meanwhile collapsed...throughout 2011 he went from 41-55-50% and finally only 31% on the last day of voting.
Let’s also not forget that 9% of the voters in Michigan were crossover Democrats and voted HEAVILY for Santorum. He got 53% of them vs. 18% for Romney, 17% Paul, 3% Newt. Do you think Santorum’s going to get that crossover boost in the upcoming states? He certainly didn’t do well in Arizona without such gimmicks.