Champlin Police Chief Dave Kolb, co-chairman of the Minnesota Chiefs of Police Association, said law enforcement groups object to any bill they view as leading to the expanded use of marijuana.
"If the bill becomes truly medical, we'd be neutral," Kold told The Associated Press before Tuesday's hearing.
Opposition from law enforcement was a chief reason why then-Gov. Tim Pawlenty vetoed a similar bill in 2009, and Gov. Mark Dayton has aligned himself with law enforcement on the current bill.
Kold also said the legislation needs to limit the ailments for which marijuana could be prescribed. He named multiple sclerosis and glaucoma as examples. Kolb said the bill's current standard of debilitating pain was "ripe for abuse."
Autumn Leva, legislative analyst for the Minnesota Family Council, testified to that point. She said that since Colorado passed its medical-marijuana law in 2000, 94 percent of those receiving permission to use marijuana were treated for chronic pain — not the grave illnesses many of those who spoke to the committee Tuesday depicted.
Kolb also said the bill needed to place medical marijuana under a pharmacy-dispensing regime comparable to the Minnesota Prescription Monitoring Program. That system helps prevent abuse of controlled substances such as Percocet, a painkiller.
"If they're going to treat it like a medicine, then treat it like a medicine," Kolb said.
Dr. David Thorson, chairman of the Minnesota Medical Association board of trustees, said his group hasn't yet taken a position on legalizing medical marijuana due to the lack of "evidence that's double-blinded to say where marijuana is truly a benefit for a variety of illnesses."
But Dr. Suzanne Sisley, a psychiatrist and internist who researches medical marijuana at the University of Arizona, said the paucity of data is because of one reason: The U.S. government approves projects that highlight marijuana's negative effects and blocks those that might show its palliative value.
"It makes it almost impossible to do medical-marijuana research," she told the committee.
Medical marijuana is allowed in some form in 20 states and Washington, D.C.