SAN DIEGO — Federal law does not pre-empt state law in a court battle over the licensing of medical marijuana, an appeals court has ruled. San Diego and San Bernardino counties had argued that issuing identification cards to eligible users, as required by the 1996 state law, would violate federal law, which does not recognize the state measure. But the appeals court concluded Thursday that ID card laws ‘do not pose a significant impediment’ to the federal Controlled Substances Act because that law is designed to ‘combat recreational drug use, not to regulate a state’s medical practices.’ San Diego supervisors had sued to overturn the state law after it was passed by voters in 1996, but a Superior Court judge ruled against them in 2006. The county appealed last year and was joined by San Bernardino. The counties have 40 days to either appeal Thursday’s ruling to the California Supreme Court or implement an ID card program. ‘The court didn’t really get to the key issue,’ said Thomas D. Bunton, senior deputy county counsel in San Diego. ‘(Federal law) clearly regulates medical practices. It says marijuana has no currently accepted medical use.’