Why shouldn't I change my mind?

The logic of my prewar shift on invading Iraq has now been doubly confirmed. I believe that the neoconservative movement, with which I was associated, has become indelibly associated with a failed policy, and that unilateralism and coercive regime change cannot be the basis for an effective American foreign policy. I changed my mind as part of a necessary adjustment to reality.

What has infuriated many people is President Bush's unwillingness to admit that he made any mistakes whatsoever in the whole Iraq adventure. On the other hand, critics who assert that they knew with certainty before the war that it would be a disaster are, for the most part, speaking with a retrospective wisdom to which they are not entitled.

Many people have noted the ever-increasing polarization of American politics, reflected in news channels and talk shows that cater to narrowly ideological audiences, and in a House of Representatives that has redistricted itself into homogeneous constituencies in which few members have to appeal to voters with diverse opinions. This polarization has been vastly amplified by Iraq: Much of the left now considers the war not a tragic policy mistake but a deliberate criminal conspiracy, and the right attacks the patriotism of those who question the war.

This kind of polarization affects a range of other complex issues as well: You can't be a good Republican if you think there may be something to global warming, or a good Democrat if you support school choice or private Social Security accounts. Political debate has become a spectator sport in which people root for their team and cheer when it scores points, without asking whether they chose the right side. Instead of trying to defend sharply polarized positions taken more than three years ago, it would be far better if people could actually take aboard new information and think about how their earlier commitments, honestly undertaken, actually jibe with reality -- even if this does on occasion require changing your mind.