The Dirt Gap: 2012 version

Obama appears to be winning in the Electoral College in almost all models, but Nate Silver's 538 blog has a map up of what the electoral college results would look like if Obama's lead deteriorated:

But suppose there is a deterioration in his polls between now and Nov. 6 — or that the polls have overestimated his standing across the board. And so Mr. Obama wins the states where he has at least an 85 percent chance of victory in the forecast, but no others. Then we’d be left with the following map ...

This distribution of states would produce a 269-269 tie. I'm not particularly interested in trying to forecast this election, but I am interested in what drives the results. This map is useful because it shows the red-blue divide in a perfectly even election. That's not a realistic scenario, but it is a useful one. The Red-Blue map came to major prominence during the protracted 2000 election in what was virtually a tie.  

What we see once again is the dirt gap phenomenon I identified after the 2004 election. The Democrats carry the Northeast coast, the Great Lakes states, and the West Coast, while the Republicans carry the interior and the Southeast coastal states.

I noted in 2005 that:

Let's look at the 50 most populous metropolitan areas in the country. Of the ones in blue states, 73 percent of their population lives in cities, such as New York, Los Angeles, and Chicago, where physical growth is restricted by unbridgeable water, compared to only 19 percent of the population of the biggest red state metropolises, such as Dallas, Atlanta, and Phoenix. 

The Law of Supply and Demand controls housing prices. The greater supply of available land for suburban expansion in red metropolises keeps house prices down.

Lower housing prices make for more affordable family formation, which makes the "family values" party more appealing.

Just looking at the map, it's easy to make up off the top of my head plausible sounding geographic explanations for the handful of anomalies. 

- The largest is why the coastal states of the Southeast are redder than the coastal states elsewhere. That's because cities tend to be inland out of hurricane range. Galveston was the metropolis of the Texas coast until the 1900 hurricane, after which Houston took over.

- Indiana is a red state that touches the Great Lakes, but the city of Gary area is rather depopulated, and other areas near Lake Michigan are more likely low cost exurbs of Chicago.

- New Mexico doesn't have many illegal immigrants, but it does have lots of Hispanics and American Indians. 

- The most curious anomalies are Minnesota and Vermont. Minnesota touches the Great Lakes at Duluth, but is largely inland. I guess you could call it the Moynihan Memorial Canadian Border Effect.

- Oregon isn't really a coastal state (Portland is well inland), but it pretends to be using zoning laws against exurban sprawl.

- In the noncontiguous states, huge Alaska and small Hawaii are the expected colors.

But, that's about all it takes to explain away the whole map, which suggests my electoral model continues to have some explanatory power.