Supporters of Proposition 8 may already suspect the outcome of today’s ruling in the case challenging California’s ban on same-sex marriage.

In court papers filed Tuesday night, lawyers for the Proposition 8 defense team asked Chief U.S. District Judge Vaughn Walker for a stay of his ruling if the outcome is to declare the law unconstitutional. The motion indicates that the Proposition 8 lawyers will immediately ask the 9th U.S. Circuit Court of Appeals to review the ruling if Walker rules against them.

“A stay is essential to averting the harms that would flow from another purported window of same-sex marriage in California,” they wrote.

The San Francisco judge’s ruling is expected to be released between 1 and 3 p.m. today.

Walker is ruling in the unprecedented trial of a lawsuit challenging Proposition 8 as a violation of the federal constitutional rights of gay and lesbian couples. The case marks the first federal court test of a state law banning gay marriage.

Walker has already refused to allow same-sex couples to marry while the legal challenge is pending, finding that it would create too much uncertainty in the state. Legal experts do not believe same-sex marriages will be permitted immediately, even if the judge overturns Proposition 8, because of the lengthy appeals ahead.

The case will not impact the roughly 18,000 same-sex marriages that took place in 2008, before Proposition 8 went into effect and after a state Supreme Court ruling that briefly legalized same-sex nuptials.

Contact Howard Mintz at 408-286-0236.