NOGALES, Ariz. (AP) - As he patrols the Arizona-Mexico border, deputy Paul Estrada laments how easy it is for smugglers to move drugs into the U.S. In a mere month, he and his colleagues could confront a new challenge: legal marijuana.

Five states will vote Nov. 8 on whether to allow recreational pot, including Arizona and California, the first two border states to consider the idea.

If Arizona's measure passes, pot shops would soon arise in a place that has long been a center of drug smuggling. In cities such as Nogales, smugglers are seen almost daily scaling the border fence with backpacks of weed.

Law enforcement leaders worry that legalization will drive cartels to sell more hard drugs. Advocates say it will undercut the cartels by eliminating a key segment of their business.