The U.S. Supreme Court has rejected without comment a challenge to California's Proposition 215 filed by a pair of counties, the San Francisco Chronicle reported May 19.

The high court rejected a case filed by San Diego and San Bernadino counties centering on the argument that the medical-marijuana law forced the counties to endorse violations of federal drug laws by issuing identification cards to medical users. The cards are intended to prevent state-sanctioned medical users from being prosecuted on drug charges by state and local police; the two counties have refused to issue the medical-marijuana IDs.

"We are disappointed that the court did not take the case to resolve what we believe was a conflict between federal and state law," said Thomas Bunton, a lawyer for San Diego County.

ACLU lawyer Graham Boyd said the case had been "the most threatening ... to state medical-marijuana laws, the only one that tried to invalidate state laws."

"No longer will local officials be able to hide behind federal law and resist upholding California's medical-marijuana law," added Joe Elford, lawyer for Americans for Safe Access.