Nate Silver predicts both Michigan and Arizona will go for Romney:
Michigan: Romney 38.7%, (55% chance of winning); Santorum 38.0% (45% chance of winning); Paul 12.6%; Gingrich 9.9%
Arizona: Romney 43.4%, 99% chance of winning; Santorum 27.3%; Gingrich 19.2%; Paul 10.2%
I'm hoping that the presence of independents and Democrats in the Michigan primary can swing the state to Santorum. The only problem is that Romney had a strong lead with early voting, making the current tie in polls not reflective of votes he's already banked. But we shall see tonight. If Santorum wins Romney's home state, it will be a huge blow to his chances at the nomination, as the GOP establishment will start speaking openly about the weakness of the current field.