回复: It is a nice map of rough pattern, although the red or blue

means the Republicans or Democrats are the majority (>50%), respectively.  So for example, all places w/ between 51% and 100% Democrats will be represented by blue. Most places are therefore purple, with different shades.  Certainly there is a gradient of Democrat (Progressive) to Republican (Conservative) domination from the coast to heartland.  That's probably true in most countries (certainly in China).