The high-profile battle over California's Proposition 8 has been touted as the case that could force the Supreme Court to face the issue of same-sex marriage. But now that Judge Vaughn Walker had decided that Prop 8, which banned same-sex marriage in California, is unconstitutional, the possibility is real that the case might never make it on appeal all the way to the Supreme Court.

That's because the advocates of Prop 8, who are launching the appeal, may not have the necessary "standing" to carry it forward. The case is titled Perry v. Schwarzenegger, with Gov. Arnold Schwarzenegger and other officials in the position of defending the ballot initiative. But those officials, who are sympathetic toward gay marriage to varying degrees, are not inclined to appeal Walker's ruling.

Under Supreme Court precedent, it's unclear that proponents of legislation would have standing to defend it if state officials are not themselves defending it, because they can't show that they are suffering the necessary injury. In Arizonans for Official English v. Arizona, a 1997 case, the Court expressed "grave doubts" about the ability of such groups to challenge rulings that strike down ballot initiatives.

"There is a very serious standing issue," said George Washington University Law School associate dean Alan Morrison, a longtime expert on standing and civil procedure. The Arizona precedent , he said, "came right up to the edge" of saying there was no standing for groups like those that favor Proposition 8. Morrison also noted that since that ruling, new members like Chief Justice John Roberts Jr. and Samuel Alito Jr. have joined the Court and are "no friends of expanding standing." Setting high standards for standing has been one of several gatekeeping procedural doctrines conservative justices have used to weed out what they view as excessive or frivolous litigation from the courts.

Morrison adds that Walker's findings in his decision -- including the finding that same-sex marriage causes no harm to those in traditional heterosexual marriages -- weaken the case for standing for the Prop 8 proponents. "There is no evidence that any persons are going to be harmed," Morrison said.

Proponents of Prop 8 say they can overcome the standing hurdle because at an earlier stage of the litigation, they were allowed the status of intervernors, and because their role in creating and launching Prop 8 gives them enough "particularized interest" to legitimately appeal Walker's decision.

Cornell Law School professor Michael Dorf, while sympathizing with Walker's decision, wrote recently on his blog that a good argument can be made for standing when state officials are reluctant to defend a successful ballot initiative. "The ballot initiative process is available precisely because the People cannot always trust their elected representatives to carry out their will," said Dorf, a former law clerk to Justice Anthony Kennedy. "Thus, when elected officials decline to defend a ballot initiative in court, they are directly frustrating the whole point of the ballot initiative process. Perhaps that is their prerogative, but if so, it makes sense for someone else to come in to defend the ballot initiative's constitutionality."

For another view of the standing issue, check out this post at SCOTUSblog.