Looking up the demographics of these counties, it looks like many (Hidalgo, Hamilton, McHenry, Osceola, Prince William, Kane, Salt Lake, Mecklenburg, Loudoun, Riverside) are fast-growing. Are these counties being filled with types of people who generally vote Democratic, or did Obama have a greater appeal to these communities than Kerry did?
Yes.
Some of it is driven by much higher minority turnout and Latino support for Obama (Hidalgo, Osceola, part of Mecklenburg), some of it is driven by middle-class and affluent suburbs feeling the pain this year and not connecting with Republicans at all, some of it is a combination of the latter and Chicago allegiances. You can be sure that lots of those Obama voters were Bush voters in '04 in places like Hamilton County, IN and Loudoun County, VA.
