“If there were a fervent ideological foundation,” Limbaugh said, “if there was a substantive reason of believing in Governor Christie, then whether he lied wouldn’t matter. They’d be out there defending him left and right just to make sure the Democrats don’t get away with this.”

It may sound unseemly, but Limbaugh, I suspect, is absolutely correct. At the macro level, tribalism might be bad for society. But at the micro level, it makes complete sense. The first thing a lot of people do when they go to prison is join a gang (as the son of a prison guard, a disproportionate number of my stories relate to prisons; I suspect an accountant’s son is prone to talking about numbers). They do this for protection.

As much as we would like to pretend otherwise, politics, I suppose, isn’t terribly different. You and I need someone watching our backs when the other side tries to shank us in the courtyard. (This, of course, is one of the many forces pushing politicians to the right or the left. It’s not just about gerrymandering. Moving to the right or left is a rational decision based on the perfectly logical assumption that you may one day need protection.)