This morning on Twitter, superstar Slog commenter Joe Szilagyi asked this question: “So what happens if the 9th [U.S. Circuit Court of Appeals] affirms the decision to toss Prop 8, but the Supremes decline to take it up?” After I retweeted the question, local politico Anne Martens replied, “Then the ruling of unconstitutional stands.”

Well, news broke a couple hours later that the the case was appealed to the 9th Circuit, thereby elevating the question of Prop 8’s future—and rights of same-sex partners—to the nation’s penultimate strata of justice (and drawing a path to possibly reach the Supreme Court). So indeed, what could happen now that Prop 8 has been declared unconstitutional by one federal court and two more courts have a stab at it?

I posed that question this afternoon to Jon Davidson, legal director of Lambda Legal, which has filed an amicus brief in the case and stands as one of the county’s strongest litigators on LGBT rights.

What the 9th Circuit Could Do:

Generally speaking, Davidson says, “If the 9th Circuit upholds the outcome, then Prop 8 would be struck down and same-sex couples could marry again in California, and the voters of California could not do anything about that in the future.”

In a more specific outcome—if the court rules using precisely the same reasoning as yesterday’s ruling from Justice Walker—Davidson continues, “then same sex couples would be allowed to marry in all nine states in the 9th Circuit, including Washington…. But the ruling would be only binding in the 9th circuit.”

That would be the best possible outcome for the gays (both in terms of more people getting marriage rights and also because Walker’s ruling was definitive in finding Prop 8 unconstitutional while debunking anti-gay myths). But it’s unlikely, Davidson says, because the 9th Circuit could be inclined to avoid a ruling that legalizes gay marriage in all nine states.

“They might say that we don’t have to decide if same-sex couples have a fundamental right to marry, and we don’t have to decide if it denies equal protection to deny them the right to marry in general,” Davidson explains. Instead the court could push for a more nuanced distinction between states based on their existing laws: “In a state like California, where the couples are given all the rights of marriage through domestic partnership, there is not a legitimate state reason to deny them the status and name of marriage,” he says. “They could say the only reason they are being denied that status and name is to single them out as different and unworthy of marriage—and the state cannot do that. But they would not decide whether or not a state might be required to allow same-sex marriage.”

“Depending on how narrow they rule, it could apply to just California, where there are 18,000 same-sex couples who are currently married," Davidson continues. "Or it could cover California, Oregon, Washington, and Nevada—which are states that [already] provide comprehensive partnership rights.”

In other words, it’s more likely the 9th Circuit court may decide that states can’t allow an unconstitutional separate-but-unequal distinction between domestic partnerships and marriage.

That sort of narrow ruling would create a couple potential advantages for the Supreme Court.

If the Supreme Court Refuses to Hear the Case:

This narrow ruling from the 9th Circuit sidesteps the big scary question of legalizing gay marriage, so the court could—to answer as Joe's questions gets to—let it stand. “Depending on how they rule, the Supreme Court might be less interested in hearing the case," Davidson says. "In a ruling that just concerns California only, where the couples can already get the legal rights of marriage, it raises a less broad issue.”

So if the Supreme Court refuses to take it, Washington could be in a very good position to benefit from legal gay marriage because we already have a compressive domestic-partnership program on the books.

After the jump: What could happen if the Supremes take the case.

...Barack Obama's Harriet Miers just got confirmed to the Supreme Court.