San Francisco — A landmark ballot measure banning affirmative action in public hiring, contracting, and college admissions, approved by California voters in 1996, violates the U.S. Constitution’s equal-protection guarantees, Attorney General Jerry Brown said on Wednesday in a letter to the state’s Supreme Court.

Mr. Brown’s nonbinding opinion says that the 1996 measure, Proposition 209, is unconstitutional because it fosters discrimination by prohibiting race- and gender-conscious programs that are allowed under the 14th Amendment to the U.S. Constitution. The Supreme Court had requested the opinion in a case considering the legality of racial and gender preferences in a San Francisco contracting ordinance.

“Ironically, by effectively disadvantaging racial minorities and women in the political process, without an evident compelling governmental reason for doing so, [Proposition 209] seems to accomplish the very evil it purported to eliminate … racial and gender discrimination,” the attorney general’s brief says, according to the San Francisco Chronicle.

The case, Coral Construction v. San Francisco, is the first time in nearly a decade that Proposition 209 may receive serious legal scrutiny from the Supreme Court. The attorney general’s opinion does not explicitly ask the court to invalidate the measure, which amended the state’s Constitution, but Mr. Brown did propose narrowing Proposition 209 to allow for programs that are acceptable under federal law.

Mr. Brown, a journeyman politician who is expected to run for governor in 2010, has disagreed with other state laws as well, notably Proposition 8, the state ballot initiative that in 2008 banned same-sex marriage. —Josh Keller