While marijuana use continues to gain social and even legal acceptance throughout a growing portion of the United States, it remains strictly prohibited for U.S. military personnel serving, living, or even visiting states that have done away with the drug’s prohibition. In America’s more progressive neighbor to the north, however, recreational marijuana use is slated to become legal for everyone in October — and that includes members of the nation’s armed forces.

The broad legalization of recreational marijuana use in Canada poses some interesting challenges for military leaders that now find themselves tasked not only with shifting policy in a manner that allows for a mood altering substance that was previously prohibited, but also with managing the perceptions of allies engaged in joint operations all around the globe.

Canada is the first G7 nation, and only the second developed nation in the world, to pass specific legislation legalizing the recreational use of marijuana. As such, Canadian military leaders have taken a number of steps aimed at assuring allies that, while Canada may have legalized marijuana, their troops will not be glassy eyed and munching on Cheetos in any combat zones.

Some of the new policies established in a directive released on Friday sound quite a bit like rules pertaining to alcohol consumption in the U.S. military — service members are prohibited from using marijuana within 8 hours of duty, for instance. Some others are unique to the drug, however. Service members are barred from marijuana use for 24 hours prior to the use of any weapons system or vehicle, and for 28 days before serving aboard a military aircraft.

Canadian commanders are under orders to look for signs of marijuana use in their troops, which would mean they had ingested (smoked, eaten, or otherwise) the drug more recently than eight hours prior to their post. The symptoms outlined by the Canadian military regulation include:

  • Odor of cannabis
  • Glassy or red eyes
  • Unusual talkativeness
  • Slow reaction
  • Inattention
  • Lethargy
  • Unsteady gait
  • Poor coordination
  • Anxiety

That list of symptoms may seem subjective, but it does speak to the complexity of legalizing a substance that can’t be easily tested for in this new context. While it may be fairly routine to test for the presence of marijuana in a soldier’s system, there is no standard “breathalyzer” type test than can be used to determine if marijuana had been ingested recently. This is likely why use of marijuana is banned for 28 days prior to flight duty, as pilots could then be tested effectively. If they were authorized to use marijuana two weeks prior to flight duty instead, they could potentially test positive for the drug, despite not having used it in any way for weeks.

“We’ve made the policy document very explicit as to when it can be used and when it cannot be used, and who is prohibited from using, and we go to a large extent to protect our operational capability.” Lt. Gen. Chuck Lamarre, head of personnel for the Canadian Armed Forces, told the press earlier this week.

The new regulations also bar marijuana use during “an international operation, exercise or collective training,” unless the exercise takes place in Canada and those using it are on authorized leave. Likewise, no Canadian soldier is permitted to use marijuana while serving outside of Canadian borders, meaning the use of marijuana is prohibited on deployments.