The polling in Michigan is too close to call; Nate Silver says Romney and Santorum are essentially tied.

People sometimes apply the term “tossup” a bit too broadly, using it to refer to anything close enough that they don’t want to render a prediction about it.

In Michigan, however, the term is appropriate. Rick Santorum, who once trailed Mitt Romney badly in the state, then surged to a clear lead there, then saw Mr. Romney regain his footing and pull back ahead, appears to have some late momentum in the race — perhaps just enough to win, and perhaps not.

It’s kind of amazing that Santorum’s statement that JFK made him “want to throw up” hasn’t damaged his popularity; in the past, statements like that would have pretty much ended a campaign. But Santorum spouts one crazy line after another, and his popularity just keeps growing. It’s an indicator of how far to the right the base has swung — and it’s why I say the Republican base has gone wacky.