The argument has been made that they lack standing, that is, aren't entitled to an appeal, because they aren't representing the state, and under some forms of appeal, private parties aren't allowed to stand in for the state.
Chris Geidner, an attorney who follows the Court, writes,
Although the argument was not fully laid out in the filing on Friday, it looks quite weak to me on the legal merits. All of the cases cited by plaintiffs appear from my review to relate only to instances where permissive intervention was granted and not intervention of right, as the proponents have here. Additionally, the cases cited appear to involve situations in which the state whose law or initiative was at issue did itself defend the law and, at some point in the appellate process, decided against appealing a lower decision. Here, of course, the intervening defendants were the only individual or entity defending the amendment even at trial.
If there were no appeal, Judge Walker's ruling would stand--but only with respect to California.
And of course, the bad guys would go apoplectic about "activist judges".
And if the state government were to change...then would the state be able to mount an appeal after the fact? Whitman is doing depressingly well against Brown. Is there a statute of limitations on appeal?
As Geidner concludes,
The case laid out at trial by the legal team led by Ted Olson and David Boies was impeccable. The argument -- legally, publicly and morally -- was nearly flawless. For all of the reasons described above, however, I see fighting the decision of the intervening defendants to appeal as a potential -- and unnecessary -- misstep.
I would keep the stay, and let the appeal go forward. That's me. you lawyer types, your thoughts?