But since the 1980s, the debate has changed. Whereas in the past the debate was about what our policy should be, today the argument is really about whether we should have a policy at all. Because if you don't care about enforcing existing immigration laws, you're really saying that you're not in favor of having any immigration laws at all. It is difficult to think of another sphere of public policy in which liberals would be nearly so cavalier about lawbreaking.

The most important immigration policy is to enforce the policy, whatever it is. Then, if it's not working, you can change it. But by turning a blind eye to illegality while spouting empty rhetoric, you incite populist rage from citizens who don't like being played for suckers.

If I had my druthers, in 2001, Bush would have pursued a real clampdown on illegal immigration while at the same time expanding legal immigration, including from Mexico. I don't even mind the idea of a one-time amnesty for illegals, if in fact it is a one-time deal. But again, a system in which we declare it's a one-time amnesty but mean nothing of the sort means that we have no policy at all.

The White House says it cares about enforcement, but Bush's credibility - indeed all of Washington's credibility - on illegal immigration is simply nonexistent. Bush and his supporters have bought into the idea that being pro-enforcement is anti-immigrant, which is why every move he makes on the issue is the political equivalent of Foghorn Leghorn trying to walk through a field of garden rakes. Conservatives dislike being called bigots and yahoos by liberals. They're even more vexed when such barbs come from the leader of their own party.

But those same conservatives have stepped on their own garden rakes because they've allowed themselves to be cast as the villains in one of America's greatest stories.