PHOENIX (AP) — An Arizona Supreme Court decision Wednesday overturns a 2012 state law that made possession or use of medical marijuana on university and college campuses a crime.

The justices said the Legislature didn’t have legal authority to enact the 2012 prohibition because it effectively changed Arizona’s medical marijuana law in violation of state constitutional protections for voter-approved laws.

The medical marijuana law approved by voters in 2010 prohibited possession in certain places, but the ban didn’t include higher education campuses.

The decision vacates the marijuana possession conviction of a man whose Arizona State University dorm room was searched after police found him sitting on a street with a medical marijuana identification card in his pocket.

Police found marijuana in the man’s dorm room.

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The decision follows one in which a lower court ruled that colleges and universities can prohibit medical marijuana on campuses but the state Legislature can’t make it a crime.

Arizona’s 2010 voter-approved medical marijuana law allowed cardholders to possess small amounts of marijuana, but it prohibited possession in prisons, schools and on school buses.

The Court of Appeals overturned the Legislature’s 2012 addition of college and university campuses to the off-limits list.

The Court of Appeals said the 2012 law violated state constitutional protections for voter-approved laws.

However, the ruling also said colleges and universities can use their own rules to forbid possession of medical marijuana.