SAN FRANCISCO (AP) — California's highest court says local governments have legal authority to ban storefront pot shops within their borders. The California Supreme Court ruled Monday that cities and counties can use their zoning powers to keep out medical marijuana dispensaries. The unanimous ruling came in a legal challenge to a ban the city of Riverside enacted in 2010. The advocacy group Americans for Safe Access estimates that another 200 jurisdictions statewide have similar prohibitions on retail pot sales. Marijuana advocates had argued that allowing local government to bar dispensaries thwarts the intent of the law California voters approved nearly 17 years ago that legalized marijuana use for health purposes.