who votes in primaries? hardcore political types at the extreme ideological ends of their respective party
who votes in a primary that was already rendered meaningless by its own party? really hardcore political types
you can't compare the michigan primary to the general election...
and, my take is that those people who voted undecided were not voting AGAINST HC, they were voting (symbolically, in an already meaningless event) FOR Edwards/Obama
having a bad candidate on the ballot depresses turnout for that party; it does not boost the turnout for the opposing party