Locked-in Voters

Jay Cost makes a good point about the weakness in most models which try to predict the presidential vote based on a few factors (e.g. economic growth, etc.):

So I would say that 90 percent of the vote is pretty well set. And this is the biggest reason that I am skeptical of these predictive models -- they usually fail to account for the fact that there were simply more gettable voters for Ike in 1956, LBJ in 1964, Nixon in 1972, or even Reagan in 1984. They assume that a president today can still win 60 percent of the two-party vote -- even though this was a regular occurrence before 1988 but has never happened since. And it has not happened since because the two parties have finally, after years of struggle and back-and-forth, locked down roughly 45 percent apiece.

 http://www.weeklystandard.com/blogs/morning-jay-90-percent-electorate-locked_642061.html

One quibble -- I don't think the re-alignment process is over.  The Tea Party demonstrations brought out an incredibly diverse group of people.  While the label "tea party" has beeen sufficiently branded by the news media such that it won't be an effective rallying cry for the future, the sentiments that gave rise to the demonstration have only been growing.

The new divide is flyover country vs. the beltway elite.  Glenn Reynolds linked to this article the other day.  http://spectator.org/archives/2010/07/16/americas-ruling-class-and-the   Although written, two years ago, the trend therein identified has only gotten stronger.

Republican and Democratic office holders and their retinues show a similar presumption to dominate and fewer differences in tastes, habits, opinions, and sources of income among one another than between both and the rest of the country. They think, look, and act as a class.
...
The Republican Party did not disparage the ruling class, because most of its officials are or would like to be part of it.

Never has there been so little diversity within America's upper crust.

Jay Cost says each party has nailed down about 45% of the electorate.  But he doesn't address the fact that only about 1/3 of GOP voters are very happy with the party.  They vote grudgingly for Republicans because they are horrified by the Democrats and the beltway mentality.  When a viable party or candidate emerges to tap into the disaffection with the ruling elite, a lot more realignment will take place.