The ruling that overthrew California's Proposition 8 may be allowed to stand unscathed, thanks to a nest of legal difficulties and fears of further setbacks by opponents of gay marriage.

Today, supporters of Proposition 8 filed an emergency motion with the US 9th District Court in an attempt to block Judge Vaughn Walker's ruling from going into effect next week. But opponents of gay marriage outside California are worried that the legal challenges could backfire.

A further 30 states currently prohibit gay and lesbian marriages, and a federal law – the Defence of Marriage Act, passed during the Clinton administration – allows individual states not to recognise gay marriages in other states.

By fighting the California ruling, some conservatives fear that the US Supreme Court could uphold Judge Walker's closely-argued decision and in effect overturn every ban on gay marriage nationwide – a re-run of the 1973 Roe v Wade Supreme Court ruling that effectively legalised abortion throughout the US.



Discussing the likely reaction of the Supreme Court, influential evangelical minister and Republican activist David Barton said that "the odds are 999 out of 1000 that they'll uphold the California decision," with worrying consequences:

"If they do, there's not a marriage amendment in the country that can stand. And so the problem is that instead of California losing its amendment, now 31 states lose their amendment. And that won't happen if California doesn't appeal this decision. It's just California that loses its amendment."

So far the Republicans have avoided making political capital out of the issue, preferring to focus on economic woes ahead of the midterm elections in November. Rightwing commentator Glenn Beck has also downplayed it, saying "I don't think the government has anything to do with marriage". And recent polls show a majority of Americans now support same sex marriage.

The lack of enthusiasm among conservatives is compounded by a legal issue that could make it difficult for Judge Walker's ruling to be appealed - a thorny question about who among the ruling's opponents has the legal standing to argue the case in court.

To have standing in federal court, a party must demonstrate that it has suffered a definite injury. In his ruling Judge Walker said there was no evidence that supporters of the Proposition 8 amendment would meet that test.

The state of California would have been the obvious candidate with legal standing to take the appeal forward, but both governor Arnold Schwarzenegger and attorney general Jerry Brown have said they will not appeal the decision.

Legal scholars speaking to the Los Angeles Times said opponents of gay marriage were "in a tough spot" and that the standing issue could scupper further appeals.

University of California-Irvine law school dean Erwin Chemerinsky said: "Their injury is ideological, and there is a century of precedent that ideological injury is not enough for standing. I think this lets the 9th Circuit and the Supreme Court follow well-established law and avoid the hard constitutional ruling."

But other experts disagreed. David Levine, a professor at the University of California-Hastings College of Law, told the San Francisco Examiner: "If the 9th Circuit wants to hear the case, they'll find a way. I think they will, since the case is such an anomaly and the potential ramifications are enormous."