For those unfamiliar with the terminology, "intervenors" are those who are permitted to participate as actual parties because they have an interest in the case. This is different from amicus curiae who are simply those who have something potentially useful to say. But because intervenors are parties, they must show that they satisfy the requirements for standing in federal court. "Standing" derives from the limitation in Article III of the Constitution that federal courts must address "cases or controversies" -- which the Supreme Court has interpreted in recent years as requiring that parties suffer, or are likely to suffer, "real and concrete injury in fact" as a consequence of the matter under litigation, rather than a mere "hypothetical or abstract" injury. Importantly, a general interest in seeing a law enforced does not confer standing.
Here, those who supported Prop 8 intervened on the side of defendants Schwartzenegger and the state of CA, arguing that they had an independent interest in affirming the constitutionality of Prop 8. The district court permitted intervention on the grounds that government defendants refused to defend the constitutionality of Prop 8 although they had standing. Because if even one defendant has standing, the standing requirement is satisfied, the district court did not see any need to make an independent finding of standing on the part of intervenor-defendants.
When Prop 8 proponents lost, Judge Vaughn denied the request for stay pending appeal citing, among other reasons, grave doubts as to Intervenor-Defendants' standing. The lead case here is Arizonans for Official English, 520 U.S. 43 (1997). There, everyone dropped out, including the plaintiff, who had taken a job in the private sector and therefore was no longer suffering from being a state employee unable to speak Spanish on the job. The State AG and the bill sponsor proponents tried to intervene on appeal. The 9th circuit found standing for the bill sponsor proponents but upheld the lower court finding the the "English only" rule was unconstitutional. The Supreme Court dismissed because the case was moot because the plaintiff had dropped out. The Court expressed "grave doubt" wrt standing for the initiative proponents, however.
In its order staying the effect of the district court's ruling, the Ninth Circuit explicitly directed appellants -- Prop 8 proponents -- to address the standing question raised under Arizonans for Official English.
Professionally, I have found myself in situations where I've intervened for defendants and had standing challenged. In Comcast v. FCC, Comcast challenged the FCC's vertical ownership limit on cable systems. At the time, I was at Media Access Project and we intervened on behalf of United Church of Christ (cable subscribers), PEG programmers, and writers of independent programming. Comcast challenged our standing. The DC Cir bypassed the issue by saying that since the FCC had standing, our standing was irrelevant. By the time the DC Circuit reversed the FCC, I had left MAP. Had I still been at MAP, I would have been interested in appealing for rehearing en banc, even though the FCC was not, which would have raised the standing problem presented here.
As a practical matter, Prop 8 supporters must show what "real, concrete, particularized, non-conjectural" harm they suffer as a result of the court's decision to overturn Prop 8. If they offered health insurance, or some other benefit where being married would expand eligibility, they could argue they suffer from additional expenses. But they don't. Nor can they argue that they are having their own free exercise rights violated. The CA Supreme Court made it clear that requiring the state to issue marriage certificates to same sex couples did not require any religious organization to recognize the legitimacy of these marriages from a religious perspective.
The best they can argue, as far as I can determine, is that "looking at happily married same sex couples makes us feel all ooky." Now this may not seem like a cognizable injury, but there is an argument to be made based on ASPCA v. Ringling Bros., 317 F.3d 334 (DC Cir 2003), and the environmental cases generally.
The need to establish standing has been a huge problem for private plaintiffs seeking to enforce environmental laws, or animal rights activists seeking to enforce protections against cruelty to animals. The government can act under these laws, because there is no standing requirement when the sovereign acts to enforce an existing law. The issue arises when a private litigant seeks to enforce these rights via the "citizen suit" provisions of these acts. While it is a fairly straightforward matter to identify my real, concrete injury-in-fact if you build a sewage treatment plant next to my house without following clean air and clean water requirements, it is harder when it comes to things like designation of the polar bear as an endangered species.
Which brings me to the tortured elephant in the title of this post. ASPCA v. Ringling Bros dealt with an elephant trainer who had worked with a particular elephant at Ringling Bros. This trainer -- now no longer employed by Ringling Bros. -- maintained that the elephant was 'trained' in a cruel manner that violated federal laws prohibiting animal cruelty. This trainer alleged that he would go to the circus to see his friend the elephant and that he, as a professional elephant trainer, could tell the elephant was still being treated cruelly. The emotional distress of seeing his friend the elephant so abused, he argued, constituted an injury in fact.
The District Court dismissed for failure to meet the Article III standing requirement. The DC Circuit reversed, and order the case to go to trial. The Appellate Court agreed that such a strong emotional connection could provide basis for Article III standing. Plaintiffs ultimately lost their standing claim at trial as the court found that the witness was essentially a "professional witness for hire" by the plaintiff ASPCA and did not, in fact, have any emotional attachment to the elephant.
Other environmental cases rely on similar notions of a legislatively conveyed right to certain kinds of positive emotional experiences. Standing in environmental cases frequently revolves around assertions by plaintiffs that they find this unspoiled area or that endangered animal aesthetically pleasing and that loss of this wilderness or species would engender emotional distress. Without these aesthetic considerations, it would be extremely difficult to ever find citizen standing in environmental cases.
So the issue is, can Prop 8 supporters claim injury in fact sufficient to support Article III standing on the basis of "looking at happy gay and lesbian married people makes me feel ooky." And, under the trial court resolution of the the ASPCA case, is it necessary to establish for what value of 'ooky?' Mind you, this might still run afoul of the "zone of interest" prong of standing. That is to say, the injury has to be one that the law is designed to protect me against. Environmental laws, after all, are designed to promote the aesthetic effects (and protect from the non-financial aesthetic harms) that plaintiffs cite as a basis for standing. I don't think Prop 8 was explicitly designed to protect people who feel ooky when they see happy gay and lesbian people married.
For me professionally, it will may or may not be useful in establishing that harm to diversity of views in mass media or on the Internet is a cognizable injury in fact. Viewpoint diversity, like environmental aesthetics, is difficult to prove and does not find favor with courts that like economic injury.