During MSNBC’s coverage of the Michigan primary, I believe I heard "Noron" O’Donnell report that, based on the exit polling, "only one in ten voters" in the GOP primary identified themselves a "Democrat."
This was presented as evidence to show that somehow the election was not in any way influenced by "readers of the Daily Kos website" who were encouraged to cross parties to vote for Romney.
Of course, if 10 percent of the GOP primary voters were Democrats, and all of them voted for Romney, that would more than account for the 9 percent margin of victory!
According to CNN, Romney’s margin of victory was 80,236 votes.
Just to get a ballpark idea of how many of those votes were from Democrats crossing over to vote for Romney just to keep him in the race, here’s a poll: