During his first State of the Union speech, President Obama asked Congress to help him repeal the "don't ask, don't tell" policy that prevents gay military men and women from serving openly. Late yesterday, a federal judge gave him an opportunity to end the policy by ruling that DADT was unconstitutional. Judge Virginia Phillips of California has given plaintiffs (the Log Cabin Republicans) a week to submit a proposed injunction that would stop the enactment of DADT. The Department of Justice, which was defending the federal government in the case, will then have a week to submit their objection — and any decision will likely be stayed pending appeals. While Obama objects to DADT, he has said he believes it should be overturned by Congress — as a result, his Justice Department has in fact diligently fought against the lawsuit (which was actually initially filed during the Bush administration).
This new ruling presents both a problem and an opportunity for Obama. With Democrats heading into what might just be a lame-duck session in the House (leading up to November elections, during which they very well may lose the majority), this might provide a last-minute chance to finally enact change on a policy many of them have vowed to end. If the Justice Department simply doesn't appeal the case after this ruling, "don't ask, don't tell" might just go away. If Obama waits for Congress to address the issue, a Republican-led house might reject an overturn.
However, Obama has promised to let the military follow through on studies to see how ready the armed forces actually are for a repeal, and how the implementation of one would work. That's part of why he wants to let Congress make the decision — that, and he knows all too well how good the GOP is at scaring their base to the polls when it seems like so-called "activist judges" are making wide-ranging social adjustments to the law.
In all likelihood, Obama will instruct the Justice Department to continue on an appeal. It's consistent with his previous position, but it's a stance that is awfully complicated to defend. The gays — once one of Obama's most staunch supporting demographics — have long been losing their patience with the president and his yet-unfulfilled pledges on DADT and DOMA (which he's also defended in court). This certainly isn't going to win them back.