Crossposted at trueconservative.typepad.com.
The most compelling demographic analysis I've seen lately: Alan Abramowitz's "The Incredible Shrinking Republican Base" on Real Clear Politics.
Short story: White Married Christians--the combined demographic--is and has been the base of Republicans' victories. Ignore income. Ignore gender. Ignore age. If you're white, married, and Christian, the odds are six or seven in ten that you'll vote Republican.