(San Francisco, California) California Attorney General Jerry Brown told the state Supreme Court Friday that it should invalidate Proposition 8, the voter approved amendment to the state constitution that bans same-sex marriage.

In a brief submitted to the court Friday, Brown’s office said the measure should be invalidated because it deprives people of the right to marry—an aspect of liberty that the Supreme Court has concluded is guaranteed by the California Constitution.

“Proposition 8 must be invalidated because the amendment process cannot be used to extinguish fundamental constitutional rights without compelling justification,” Brown’s brief said.

Brown argued that in order to invalidate such a fundamental right, the court “must determine that there is a compelling justification to do so.”

But in the marriage cases that the court ruled on earlier this year, striking down the ban on gay marriage “the court found that no such compelling justification exists. Accordingly, Proposition 8 must be stricken,” the brief said.

Brown also said that he believes that same-sex marriages entered into between June 16 and November 4, 2008 are valid and recognized in California regardless of whether Proposition 8 is upheld.

The position was a surprise to some. Although he personally supports same-sex marriage many thought as Attorney General Brown would ask the court to uphold Prop 8.  Brown’s office said that as Attorney General he is obligated to argue state constitutional law, which is what he did.

The court had ordered Brown’s office to submit its brief by today in reaction to legal challenges to Prop 8.

Following passage of the proposition the American Civil Liberties Union, Lambda Legal and the National Center for Lesbian Rights filed lawsuits challenging the constitutionality of the vote.  They were joined by additional suits by the cities of San Francisco and Los Angeles.

The lawsuits charge that Proposition 8 is invalid because the initiative process was improperly used in an attempt to undo the constitution’s core commitment to equality for everyone, by eliminating a fundamental right from just one group – lesbian and gay Californians.

They also say that Proposition 8 improperly attempts to prevent the courts from exercising their essential constitutional role of protecting the equal protection rights of minorities.

The suits say that under the California Constitution, such radical changes to the organizing principles of state government cannot be made by simple majority vote through the initiative process, but instead must, at a minimum, go through the state legislature first.

The California Constitution itself sets out two ways to alter the document that sets the most basic rules about how state government works, the groups said in a statement.

Through the initiative process, voters can make relatively small changes to the constitution.  But any measure that would change the underlying principles of the constitution must first be approved by the legislature before being submitted to the voters.

That didn’t happen with Proposition 8, and that’s why it’s invalid, the petitioners said.

The Supreme Court set Friday as the deadline for Brown’s office to reply and it said that in addition to hearing arguments on the validity of the vote it wanted to address what effect, if any, a ruling upholding the amendment would have on the estimated 18,000 same-sex marriages that were sanctioned in California before Election Day.

In addition to the brief from attorneys for the Protect Marriage Coalition, the umbrella group that put Prop 8 on the ballot.  It argued that the will of the people must be respected by the court and that the measure also invalidated those marriages performed prior to the vote.

The coalition has hired Ken Starr who led the inquiry into President Bill Clinton’s affair with Monica L. Lewinsky, to argue its case before the high court. It said it needed a high profile attorney because it did not trust Brown to fight for Prop 8.

The court is expected to study the briefs and then ask for comment from the litigants.  Oral arguments in the case could be heard as early as March but a ruling would not come for months after that.