I don’t enjoy trashing the decision-making of the McCain campaign, but I’d note that they announced they were pulling out of Michigan on October 2.
Obama’s margin in the polls in Michigan beforehand: Tie, 3, 13, 10.
Obama’s margin in the polls since: 5, 16, 16. I would not expect that margin to shrink.
I’m sure those Republicans running downticket are concluding, “Thanks, guys.”