Basically, the administration is trying to have this one both ways. They are defending DADT in court, and not doing it well enough (or, indeed, at all) for it to win. Why? Changing the policy is popular with some groups, but by no means with all. Avowing an intent to change the policy after the military completes its review (a review choreographed by the administration) takes the heat away from 1600 Pennsylvania and parks it on the Pentagon. It allows the administration to advocate for changing it and still look as though they are defending it in court. Neither side gets entirely what it wants, but both get something. The effect: the issue gets largely neutralized for the campaign; afterwards, all bets are off.