He's ahead in the poll of polls:
Blumenthal expects Romney to win both states tomorrow:
Even if the polls are slightly underpredicting Santorum's vote in Michigan and Arizona, should the current trends continue, Romney will probably have the votes to win both states.
PPP's early voting numbers reinforce that prediction:
Romney will go into election day with a large lead in the bank. Only 16% of Michigan voters say they've already cast their ballots, but Romney has a whooping 62-29 advantage over Santorum with that group. Santorum actually leads Romney 39-34 with those who are planning to cast their votes on Tuesday, but he'd need to win election day voters by even more than that to neutralize the advantage Romney's built up.
The Dish 