Is There Really a Moralistic Politics?

There's a certain acceptance of the inevitability and everyday practicality of, in this case, a moralistic account of the world. And today, I really think we see moralism operating across the entire spectrum. But Gramsci again and again goes back and says, you can't understand this in an abstract or mechanical way. Is there actually a real history of the Democratic Party that tells us how the party of slaveholders from Jefferson and Jackson becomes the party of Roosevelt?