Marijuana and guns

Don't they have to be convicted of possessing a controlled substance before their drivers licenses are suspended in your state?

The gun ban for marajuana users is based on an existing Federal law, 18 U.S.C. § 922(g)(3), according to the ATF. (ATF statement download link)

I doubt that a medical marijuana state would pass laws that would suspend medical marijuana users' drivers licences.

It seems your proposal should also include users of alcohol, prescription opioids, and certain flu symptom medications as well.

I consider anything that impairs a person from sanely driving on our roads to be a dangerous drug. Even if it is temporary. I have had close calls with drunk drivers and nuts that seem high on something weaving through traffic at high speeds. Many accidents are caused by drunken drivers. I don't do marijuana, but have seen people here high on it and they were in such a stupor, they were not fit to be driving. If there were nothing to stop them from getting in their cars to go shopping, they will be on the road.