The great Jay Cost is a skeptic of the argument that if a candidate wins a primary in a state, then they are likely to win the state in the general election.
Another key year is 1988. This is the best apples-to-apples comparison of 2008 that there is. That year, both parties had open nomination battles. The Democrats out-performed the GOP by a margin larger than what they have done this year, pulling in a little more than 65% of the total primary vote. Did it do them any good in the general? No. George H.W. Bush beat Michael Dukakis, 54% to 46%.
So, there is apparently no connection between Democratic primary turnout and the Democratic vote in the general. Why not? I would suggest two reasons. First, higher turnout is in many respects a consequence of drama rather than enthusiasm. In years past, the Democrats have had more dramatic primary battles that have intrigued and engaged voters. This year is no exception. Dramatic races might actually have a negative effect on the party because it drains time and money from the eventual nominee.
I would add an even clearer and more recent examples. In 2000, Iowa was a blue state, carried by Al Gore. Four years later, the Democratic ticket didn’t just include the winner of the state (Kerry); it included the candidate who finished a very respectable second place (Edwards). Together… they lost the state.
Same story with another previously blue state, New Mexico. Gore won the state in the general election in 2000; Kerry won New Mexico in 2004, 42 percent to 20 percent for Wes Clark. Bush carried New Mexico by a narrow margin in 2004.
You can go down a list of states that Democrats, at one time or another, thought were going to be competitive in 2004: Virginia, Missouri, the Nevada Caucuses, Ohio, Florida. All of those states were carried by Kerry in the primary (usually by a wide margin, and for most of that time, Edwards was still viable, and Clark and Howard Dean were still hanging around). He lost all of them in the general election.
Looking back further, George W. Bush lost the New Hampshire Republican primary by a wide margin in 2000… and carried the state against Gore.