People have a tendency to ideologically justify policies which benefit them personally, even if they are totally opposed to their politics. They also tend to be very good at detecting and denouncing this hypocrisy in their opponents while ignoring it or rationalizing among themselves.

Ideology is poisonous. It's not that people shouldn't adopt a philosophy that they feel leads to more just or effective policy, it's that once you forget the policy and the desired result and make decisions based solely on the ideology that you begin a slide down a slippery slope that leads to corruption. Conservatives are equally vulnerable to this as liberals, as the last few years have so clearly demonstrated. Ideology is NOT principle, it is a substitute for it.

All this has also been demonstrated to me quite effectively by the political discourse on this board.