The past isn't dead.  It isn't even past.

Presidential vote by county, 2008.  See that blue curving band across the deep south?

 South_electoral

http://elections.nytimes.com/2008/results/president/map.html

 

cotton

http://www.nps.gov/history/seac/beneathweb/ch13/m21.jpg

Black Population, 1990


http://www.census.gov/geo/www/mapGallery/RHOriginPD-1990.html

By the way, this effect isn't just present in Obama's victory; Democratic voting and the cotton belt have a longstanding correlation, at least dating back to Lyndon Johnson. 
 http://cstl-cla.semo.edu/renka/ui320-75/renka_papers/party_system_maps.asp

Here are 2004 election results:  Yellow is Kerry, blue is Bush.
2004 Electoral results by county
http://geoelections.free.fr/USA/elec_comtes/2004.htm

In response to StumbleUpon commenters who suggest the effect is due to urban centers voting Democratic, here's the population density for 2004. 

Population 2004
http://www.census.gov/popest/gallery/maps/PopDensCounties_2004.pdf

Since I posted this page originally, the main images have been picked up in

Pin-the-Tail
StrangeMaps (which has a nice overlay of the cotton and electoral vote maps)
Andrew Sullivan
Wonkette
The Vigorous North (with further explanation tracing this pattern back to the Cretaceous!)
Cretaceous.gif
http://jan.ucc.nau.edu/~rcb7/nam.html

Allen Gathman, 11/6/2008

 

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