In a big win for gay rights and common decency, a federal appeals court has pronounced California's Proposition 8 unconstitutional, arguing that there's no "legitimate reason for the passage of a law that treats different classes of people differently." Further, the court shot down the effort to argue that the judge on the case was biased because he is gay. Gay rights advocates are hoping that this increases pressure on President Barack Obama to declare his support for gay marriage. He has said his position is "evolving." But Obama has caught a big break because the ruling was narrow, and actually affirms his position. The key to the ruling is that it didn't pronounce gay marriage a right under the U.S. Constitution. Rather, the court simply affirmed that you can't take away by referendum a right to marry that citizens already enjoy under state law. Obama has done a great deal for the cause of gay rights, and he has left the impression that he fully supports gay marriage, even if he has not been willing to say so out loud. But even if this decision doesn't put more pressure on him to go further, Obama can point to it to reaffirm his oft-stated position that the arc of history is long but bends towards justice.