Nate Silver predicts a long night:
One word of warning: factors like early voting, crossover voting and the relatively large amount of demographic diversity within Michigan will make it tricky to call the state based on exit poll results and the first few precincts that report. For instance, if early and absentee results are reported before those cast on Election Day, as is common in some states, Mr. Romney could initially emerge with a lead that proved ephemeral. I generally take the view that the news networks are too quick to call a race — shouldn’t have we learned something from Florida in 2000 or Iowa this year? — but there is reason to be especially cautious here.
The Dish will be live-blogging from 8 pm on. Polls for both Michigan and Arizona close at 9 pm ET. (Most Michigan polls close at 8 pm ET but the part of the state on central time stops voting an hour later.)
The Dish 