SAN FRANCISCO — Chief Judge Vaughn Walker struck down Proposition 8 today, finding that it violated gay Californians’ equal protection and due process rights under the U.S. Constitution.

In a 136-page decision released just before 2 p.m., Walker said that the measure “fails to advance any rational basis in singling out gay men and lesbians for denial of a marriage license. Indeed, the evidence shows Proposition 8 does nothing more than enshrine in the California Constitution the notion that opposite-sex couples are superior to same-sex couples.”