A generation ago, then-Gov. Jerry Brown's conscientious stand against the death penalty prompted a revolt in the Legislature and eventually spurred voters to throw out his appointee as chief justice of the California Supreme Court.

Now the 70-year-old attorney general and would-be 2010 gubernatorial candidate is stirring a new storm by his legal challenge to voters' approval of a measure banning gay marriage in California.

It's a move that could pay political dividends in a June 2010 Democratic primary against another likely gubernatorial candidate, San Francisco mayor and gay marriage champion Gavin Newsom.

After initially indicating his office would defend the "will of the people" in the Nov. 4 election, Brown filed a 91-page legal brief Dec. 19 arguing that Proposition 8 violated an "inalienable right of liberty."

His intervention is hailed in heroic terms by Proposition 8 opponents – even though Brown also rejected the opponents' core legal argument challenging the initiative.

"I think Jerry Brown becomes an historic figure in this," said Rick Jacobs, chair of the Courage Campaign, which supports gay marriage. "He has shown that the attorney general can and will stand up for the rights of the minority in this state.

"I think he is Madisonian. He opposes the tyranny of the majority."

Yet gay marriage opponents say Brown is abandoning his statutory role as attorney general by refusing to represent the majority of voters who approved Proposition 8 as an amendment to the state constitution.

"It is wrong for politicians to elevate their own views of what the law should be over what the constitution says the law actually is," wrote Frank Schubert, director of the Yes on 8 campaign. "Doing so is not only illegal. It undermines the legitimacy of government itself."

Brown's legal brief argues that the attorney general's obligation to "uphold the whole of the Constitution" supersedes his role in defending a voter-passed initiative.

Brown likens his actions to that of state Attorney General Thomas Lynch, who in 1964 challenged voters' passage of Proposition 14, a measure that overturned a state law against housing discrimination. Proposition 14 – also an amendment to the state constitution – was later overturned by the U.S. Supreme Court.

Brown's increased profile in the battle comes as the California Supreme Court in March is to hear three lawsuits challenging Proposition 8. The court also will consider whether to invalidate 18,000 existing same-sex marriages.

Brown said he and his attorneys argue in a "well-thought-through" brief that the right to gay marriage is protected by guarantees of basic liberties under Article One of the California Constitution.

"Those basic guarantees of liberty mean something special," Brown said in an interview. "That certainly requires that they not be stripped away like any other state rule or statute."

He also argues that Proposition 8 should be struck down based on the May 2008 state Supreme Court decision that legalized same-sex marriage "as a basic civil right" in overturning Proposition 22 – a measure passed by voters in 2000.

Yet Brown's brief also rejects a key legal argument by No on 8 advocates who said the initiative was a constitutional revision that required a two-thirds vote of the Legislature to get on the ballot.

Brown's gay marriage brief is far from his first controversial stand on his convictions.

In 1977, the state Legislature overturned Brown's veto of a state death penalty law. And his appointment of liberal, anti-death penalty jurist Rose Bird as chief justice of the state Supreme Court led to a voter backlash and Bird's ouster from the court in 1986.

"Challenging Proposition 8 on broad, fundamental grounds is very much consistent with Jerry Brown's reputation," said Darry Sragow, a public policy lawyer and veteran Democratic political strategist. "This is a man who likes to think big thoughts. This is a challenge that is consistent with that."

Call Peter Hecht, Bee Capitol Bureau, (916) 326-5539.