As California Legalizes Pot, Laws Collide at U.S. Checkpoints

California legalizes marijuana for recreational use Monday, but that won’t stop federal agents from seizing the drug — even in tiny amounts — on busy freeways and backcountry highways.

Marijuana possession still will be prohibited at eight Border Patrol checkpoints in California, a reminder that state and federal laws collide when it comes to pot. The U.S. government classifies marijuana as a controlled substance, like heroin and LSD.