The demographic shift of America and politics

I was looking at the electoral vote projections, and comparing them with 2000, and I noticed something. If this were 2000 instead of 2004, and the election turned out the same way, Kerry would have had 7 more electoral votes than he did. Here’s how it turned out, looking at states Kerry won:

California had 54 electoral votes in 2000, 55 now, for a gain of 1 to Kerry
Wisconsin had 11 votes, now 10, for a loss of 1
Illinois had 12, now 11, for a loss of 1
Michigan had 18, now 17, for a loss of 1
Pennsylvania had 23, now 21, for a loss of 2
New York had 33, now 31, for a loss of 2
Connecticut had 8, now 7, for a loss of 1.

We’re seeing a demographic shift in this country away from the Northeast and industrial Midwest to the South and the West. I’m wondering what effect you think this is going to have politically, especially considering that the Northeast and industrial Midwest has traditionally been a Democratic base (and still is…that’s where almost all of Kerry’s electoral votes came from), and the South and West are pretty solidly Republican.

I’d be interested in knowing why all the population increase in the South and Southwest plays into the hands of the Republicans/conservatives. Are liberal/democrats simply not among the people who are moving there?