Joe and I have been arguing for over a year that the President doesn't have to enforce DADT, nor does he have to defend it in court. A number of LGBT apologists, political neo-phytes, White House lobbyists, and executive-branch-wannabes said we were wrong. But now that actual independent legal experts have looked at the issue, it turns out we were right.
From Newsweek (read the entire piece, it's quite interesting):
Some experts wonder why the administration even chose to defend the law in the first place. Turley maintains that they didn’t have to: “The president has a duty to separate his administration from an unconstitutional statute. If a statute required racial discrimination, would the president seriously be arguing that he and his administration would have to defend the statute all the way to the Supreme Court?” Many liberals feel betrayed by a president who they see as having chosen to enforce and defend a discriminatory law.
