It turns out that houses in blue cities are more expensive than houses in red cities.
Trulia chief economist Jed Kolko compared vote margins from the 2012 presidential election to Trulia's estimates of the median asking price per square foot in each of the hundred largest US metropolitan areas. The following chart plots this comparison, with red dots indicating metro areas where Mitt Romney won, light blue dots indicating areas where Barack Obama won by fewer than 20 percentage points, and dark blue dots showing areas where Obama won by more than 20 points:
While each of the three groups include cities on the lower end of the house price spectrum, nearly all of the Romney-voting metro areas had median prices lower than $200/square foot, while some of the most Democratic-leaning areas were far more expensive.
Looking at these three groups in aggregate, the median asking price among the heavily Obama-favoring metro areas was nearly twice as high as in the Republican metros:
In the Trulia blog post on this analysis, Kolko warns against mistaking correlation for causation:
"The point is not that Democrats cause expensive housing, lower homeownership, or greater inequality. Determining whether and how the political views of voters or their elected officials affect local housing markets is the stuff of scholarly research, not short blog posts. But because blue markets are less affordable, have lower homeownership, and have greater income inequality, political leaders in Democratic-leaning and Republican-leaning metros may push for different policies."
For further details, and a full list of the nation's metro areas, check out the Trulia post here.