Allen Guelzo is the Henry R. Luce Professor of the Civil War Era and Director of Civil War Era Studies, was featured in an NBCNews.com article about political and ideological polarization in America.
From NBC News:
The author and historian Allen Guelzo of Gettysburg College argues this period of polarization has been a long time brewing and resembles previous periods of sharp ideological divide in the country: the 1790s, the period of the birth of our political parties, and the tumultuous 1850’s, which foreshadowed the secession of the Southern states. The difference between then and now, he argues, is culture. “Culture is the tail that wags the dog of politics.” By this he means forces like local government, for example, move ahead on policy changes while Washington remains stuck.