One of the great differences between conservatives and liberals is that conservatives will freely admit that they have an ideology. We’re kind of dorks that way, squabbling over old texts like Dungeons and Dragons geeks, wearing ties with pictures of Adam Smith and Edmund Burke on them.

But mainstream liberals from Franklin Roosevelt to Barack Obama — and the intellectuals and journalists who love them — often assert that they are simply dispassionate slaves to the facts; they are realists, pragmatists, empiricists. Liberals insist that they live right downtown in the “reality-based community,” and if only their Republican opponents weren’t so blinded by ideology and stupidity, then they could work with them.

This has been a theme of Obama’s presidency from the start. A couple of days before his inauguration,Obama proclaimed: “What is required is a new declaration of independence, not just in our nation, but in our own lives — from ideology and small thinking, prejudice and bigotry” (an odd pronouncement, given that “bigoted” America had just elected its first black president).