Is Politics a War of Ideas or of Us Against Them?

Is the deepening animosity between Democrats and Republicans based on genuine differences over policy and ideology or is it a form of tribal warfare rooted in an atavistic us-versus-them mentality?

Is American political conflict relatively content-free — emotionally motivated electoral competition — or is it primarily a war of ideas, a matter of feuding visions both of what America is and what it should become? CONT.

Thomas B. Edsall, New York Times