SAN FRANCISCO — Proposition 8 proponents attacked Attorney General Jerry Brown on Monday for refusing to defend the measure that banned same-sex marriage, arguing that he has created a new legal theory “utterly without foundation” in the state’s case law.

“We will not mince words,” attorneys Kenneth Starr and Andrew Pugno wrote in a brief filed with the court on behalf of ProtectMarriage.com — Yes on 8. “The attorney general is inviting this court to declare a constitutional revolution.