Oremus delves deeper in the phenomenon he first took note of in Vanderbilt's recent piece, and finds that the 19 highest scoring cities on Walk Score are all in states that voted for Obama in 2008, and that "the lowest-scoring major cities, by comparison, tilt conservative: Three of the bottom four-Jacksonville, Oklahoma City, and Fort Worth-went for McCain." What, he asks, explains the correlation?
Size doesn't seem to be a determinant, but Oremus thinks that density might very well be. After noting some potential reasons for the correlation, he proposes that, "The same factors that make cities dense and walkable also make them liberal... Besides being older, they also tend to be on the coasts... That leads to both dense development along the coastline and to an atmosphere of diversity and tolerance."
Oremus sees a geographical and historical correlation as well. "Look at the walkability map and you'll see that unwalkable cities are concentrated in the South. While the northern United States developed an industrial economy, the South was dominated by agriculture until the last few decades. Whereas industry breeds density, immigration, and social mobility, agriculture requires vast plots of land and leads to an entrenched social order dominated by the large landowners."
While Oremus's conclusions are far from scientific, they provide a rich vein for debate.