SAN FRANCISCO — Attorney General Jerry Brown has come under attack for taking the unexpected step recently of questioning the constitutionality of Proposition 209, the 1996 ballot initiative that eliminated most affirmative action programs in California.

In a letter brief filed with the California Supreme Court late Thursday, the Pacific Legal Foundation condemned Brown’s stance as “political expediency” and accused him of trying to revive programs that are “relics of a long-gone era of racial politics.”