The Ninth Circuit Court of Appeals will rule tomorrow (Tuesday June 5th) on whether it will hear the Prop 8 Case "en banc", which would mean hearing the case again with a panel of 11 judges. Should they decide not to hear the case again it's likely Prop 8 supporters will try to get the case to the Supreme Court.
Normally the filing is styled as a petition for a rehearing or for a rehearing en banc. A rehearing by the original panel is not granted very often. It's possible that the original panel either determines that the petitioners have shown an obvious error, so we don't need to go en banc because we can correct it ourselves, or the panel will sometimes adjust their opinion trying to head off an en banc. They're not likely to consider granting a rehearing of their own, but you never know.
In a case like this, almost certainly the panel will refer it to the en banc court. It would then go to a judge who's called the en banc coordinator. That coordinator will send it out and say here's a petition for rehearing en banc – and they get a ton of these. But this one will get special attention.
A majority of active judges in the circuit needs to grant an en banc hearing. That's 13 votes, which is very hard to get in a circuit that has 7,000 – 8,000 appeals filed a year. They grant maybe 15-20 en bancs a year.
I think [Prop 8 proponents] are pretty disappointed with Judge Smith's dissent, which was not a ringing Scalia-like forceful "this is wrong." It was more like "we should be cautious, although there are a lot of good points here."
The Supreme Court has said more than once that the 9th circuit ought to use its en banc power to clear up problematic decisions before the cases get to us. Then there are other judges who believe that if a case is an outlier, it's the Supreme Court's job to clear it up, not the en banc court.