MINNEAPOLIS (WCCO) — The fight over legalizing medical marijuana in Minnesota again faces fierce opposition from law enforcement agencies. Gov. Mark Dayton has said he won’t support a law unless police departments sign off on it first.

In a career that has spanned more than three decades, Chief Deputy Tim Leslie at the Dakota County Sheriff’s Office knows better than anyone the damage drugs can do.

“The Dakota County Sheriff’s Department will not be supporting it,” Leslie said. “We’ve seen what substance abuse does to families and individuals.”

Leslie said about 40 percent of his jail is filled with people with drug or alcohol problems. It’s why he doesn’t see a day where he could ever get behind legalizing something he believes would make it easier to get marijuana.

“That’s kind of our view of life sometimes,” Leslie said. “We see those that try to deceive the system.”

Rep. Dan Schoen (D-District 54A) is a co-author of the bill to make medical marijuana legal.

“That’s not really the direction we’re going, we’re trying to take care of sick people,” Schoen said.

He doesn’t consider it a political move but a personal one. A colleague of his has terminal brain cancer. He’s a sergeant at the Cottage Grove Police Department where Schoen himself is an officer.

“He sees a glimmer of hope that helps better the life he may have left,” Schoen said.

But some studies have pointed out plenty of problems for police after states legalize pot for medical reasons. In Colorado, for instance, The High Intensity Drug Trafficking Area Task Force found that traffic deaths involving drivers that were high on marijuana went up 114 percent. They also found that nearly 11 percent of 12-to 17-year-olds admitted to smoking pot in Colorado. That’s much higher than the national average.

“If it was a street sign it would say: ‘Caution, rough road ahead,’ because once you start the legalization process everything kind of changes,” Leslie said.

It’s a debate that looks much different on both sides, especially to one officer and lawmaker still convinced compromise is possible.

“Let’s get there, and let’s do it,” Schoen said.

Past polls have shown statewide support for legalizing medical marijuana, but that might not be enough.

Lawmakers approved similar legislation in 2009, but it was vetoed by then-Gov. Tim Pawlenty for public safety reasons.