As Linus noted, the 9th Circuit upheld the lower court ruling that Prop 8 was unconstitutional. Dahlia Lithwick has a good piece here about how narrow the ruling is (in short, the judgment only holds that Prop 8 in particular includes animus towards gays because it was removing a right that had already been granted by California’s Supreme Court in the Marriage Cases). That particular set of facts has no analogy anywhere else and thus the ruling would be limited to California.
What Lithwick doesn’t mention is that there may be a long game that the 9th Circuit is playing here. Let’s say that at the Supreme Court, the Court finds that the 9th Circuit’s reasoning is wrong. In the meantime, more states will be passing same-sex marriage laws (Washington, maybe Maine, maybe Maryland, maybe Illinois, maybe Rhode Island). Then, the case goes back to the 9th Circuit on remand. The court of appeals still needs to schedule arguments, etc., etc. More time passes; more social norms change. Then, the 9th Circuit adopts a broader constitutional tone, more in keeping with the original Judge Walker lower court opinion. Then the case goes back to the Supreme Court. In the ensuing period, same sex marriage has become essentially normal (and may even become moot if California passes anti Prop 8).
My point is that same-sex marriage will be here to stay in California for at least some time. Even the social conservatives on the Supreme Court will probably be wary to overturn the 9th Circuit in a way that again revokes a right to same-sex marriage in California for the second time.
Court opinions matter in the short term, but in the long term, it’s all about values changes, and that’s the fight that the same-sex marriage advocates are winning. (Consider the polling on interracial marriage, which was way worse when Loving v. Virginia was passed in 1967.)