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It's been widely noted that Barack Obama's winning coalition drew up the wide ethnic, racial, gender, and sexual orientation diversity of a new and rising America, while Mitt Romney and the GOP captured the wide majority of white men. In their 2004 book The Emerging Democratic Majority, John Judis and Ruy Teixeira describe this new majority based on diverse ethnic and racial voting blocs and knowledge workers in urban "ideopolises."

Last week, I posted on Dave Troy's analysis of density and Democratic advantage. Troy's analysis finds that U.S. places essentially turn blue at about 800 people per square mile.    Troy has a new post out where he looks at the role of diversity.   Courtesy of Dave Troy: Fueled By Randomness   As with density, Troy finds some intriguing tipping points with regard to diversity based upon the racial and ethnic composition of U.S. counties. Counties turned blue at the following thresholds: 39 percent black, nine percent Hispanic, and just three percent Asian. Counties that are 45 percent white voted blue, while those that are more than 55 percent white voted red. The underlying "drivers" of American voting patterns, writes Troy, are "density and diversity" — both of which are found in larger, more populated cities and their constituent counties.

This article is from the archive of our partner National Journal.

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