Political science PhD candidate David Sparks has look at the evolution of the two-party vote:
Using county-level data, I spatially and temporally interpolated presidential vote returns for the two major party candidates in each election from 1920-2008. The result illuminates the sometimes gradual, sometimes rapid change in the geographic basis of presidential partisanship.
David notes further:
This animated interpretation accentuates certain phenomena: the breadth and duration of support for Roosevelt, the shift from a Democratic to a Republican South, the move from an ostensibly east-west division to the contemporary coasts-versus-heartland division, and the stability of the latter.
More broadly, this video is a reminder that what constitutes “politics as usual” is always in flux, shifting sometimes abruptly. The landscape of American politics is constantly evolving, as members of the two great parties battle for electoral supremacy.
Watch it play out in the video below.