Opponents of gay marriage in California on Tuesday asked the Supreme Court to overturn a federal appeals court ruling declaring Proposition 8 to be unconstitutional.

Prop 8 is the 2008 voter-approved constitutional amendment which put an end to the marriages of gay and lesbian couples taking place in the state after the California Supreme Court ruled against the state's ban on such unions. Approximately 18,000 gay couples married before Prop 8 went into effect.

In its filing, Protect Marriage, the sponsors of the measure, described the Ninth Circuit Court of Appeals ruling as “misguided.”

“Our constitution does not mandate the traditional definition of marriage, but neither does our Constitution condemn it,” the group said. “Rather, it leaves the definition of marriage in the hands of the people, to be resolved through the democratic process in each state.”

The court's ruling was crafted narrowly and applies only to California. For that reason, gay marriage advocates said they would oppose review by the high court.

“This case is about the equal rights guaranteed to all Americans by our Constitution,” said Plaintiffs' counsel Theodore J. Boutrous, Jr. “Because two federal courts have already concluded that Proposition 8 is unconstitutional, gay and lesbian Californians should not have to wait any longer to marry the person they love. We therefore will oppose the petition for a writ of certiorari. However, we recognize that this case presents constitutional issues of national significance, and are ready to defend our victories before the Supreme Court.”

HRC President Chad Griffin, who co-founded the American Foundation for Equal Rights (AFER) to bring the case to trial, said he was confident that the Supreme Court would uphold the ruling.

“Despite the losses in two federal courts and millions of dollars wasted, the proponents of Proposition 8 persist in their effort to hurt California families,” Griffin said in a statement. “Even if the Supreme Court decides to review the Ninth Circuit's decision, I am confident that they will come to the same conclusion as the judges, appointed by Democrats and Republicans, who have heard the case before them: Prop 8 simply cannot stand.”

(Related: David Blankenhorn, Prop 8 witness, reverses course on gay marriage.)