This is a section I have been giving some thought to recently, why not see if I can’t make arguments against myself; or hopefully, someone else?
I think that it is quite clear that the Executive Branch of California violated its Constitutional duty to protect the California Constitution; and to faithfully execute the law and will of the People when they failed to appear in Court on behalf of Prop 8. I take issue with the notion that failure to do so resulted in the denial of an opportunity for the Supreme Court to reach a good decision on the merits of Prop 8.
On the same day Prop 8 was decided, the Supreme Court issued a ruling on DOMA. The DOMA decision placed a great deal of emphasis on the fact that States traditionally decide what marriage is, and the benefits that go with it; it was a decision emphasizing state sovereignty. It would be quite paradoxical for the Court to issue one ruling saying that States are in charge of defining marriage, and saying that the State is not allowed to define marriage in the other. It is very likely that had the Court decided Prop 8 on the merits, same-sex marriage proponents would have actually taken a massive leap back.
In conclusion, California should have defended Prop 8, but failure to do so is probably the reason same-sex marriage proponents did not receive disappointing news on June 26,2013.