Two Cheers for the Supreme Court on LGBT Rights: Because the plaintiff won his suit and no representative of the government of California was willing to defend the constitutionality of Prop 8, there was according to the majority no case to resolve and hence the Supreme Court lacked jurisdiction. The result is that Prop 8 will be struck down (as the district court ruled) without creating a federal right to same-sex marriage in any other state.
In my view, resolving the case on standing grounds is the worst of the "good" outcomes that could have been reached. Allowing lower court decisions holding laws unconstitutional to stand without further review because the current government won't defend them is a potentially dangerous precedent, further narrowing standing rules that are already too narrow. The outcome is preferable to upholding Prop 8 but is definitely inferior to any opinion ruling Prop 8 unconstitutional on the merits.