Now that more states across the nation have legalized marijuana for recreational use, law enforcement agencies are being forced to retire drug-sniffing dogs – one of the primary tools they use in discovering illegal contraband during roadside shakedowns. Unlike human officers, these animals cannot be retrained to understand that pot is now acceptable in certain parts of the country, so they are becoming increasingly more useless in drug enforcement operations. The situation begs the question, should canine trainers continue to teach future generations of dope sniffers that marijuana is an illegal substance or amend the system in preparation for an entirely legal nation?

Although this is not yet a problem in most states, it is for police in places like Colorado, where marijuana has been legal for the past six years. “A dog can’t tell you, ‘Hey, I smell marijuana’ or ‘I smell meth,’” Tommy Klein, the chief with the Rifle Police Department, told the New York Times. “They have the same behavior for any drug that they’ve been trained on. If Tulo [the department’s drug dog] were to alert on a car, we no longer have probable cause for a search based on his alert alone.”

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In some legal marijuana states, like California, Maine, Vermont and Oregon,  drug dogs are no longer being trained to detect marijuana. Even though situations could still arise where it is necessary for K-9 units to pick up the scent of weed (interstate drug traffickers) the issues with probable cause have rendered them obsolete. Law enforcement in Canada, where the herb went fully legal back in October, are dealing with this, as well.

Interestingly, even states where marijuana is still considered an outlaw substance, police are now requesting that their drug dogs not be trained to detect marijuana. Ron Cloward, who trains dogs for police departments all over the country, told the Times that a Texas police department recently requested that their new drug dog not come with the power to sniff out weed. It’s a way of hedging their bet. While marijuana is illegal in Texas, some police organizations understand that it won’t stay that way for long.

“They had the feeling there could be some changes coming there, and they wanted to plan ahead,” Cloward said.

Some state courts are overturning drug convictions because K-9 units that alert on marijuana, as well as other drugs, are considered a peril to investigations. It is for this reason that dogs are having to be replaced with younger versions.

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Still, not every state is taking such a proactive approach to this problem. In Kansas, which borders legal Colorado, drug dogs continue to be trained for marijuana. “The issue is on our radar, and we watch and research what states are doing as legalization crawls across the United States, but as of today all of our dogs are still imprinted on marijuana odor,” said Chad McCluskey, the master trainer for the Kansas Police Dog Association. “We are not considering a change to that approach.”

While many prohibition states might be resistant to purchasing drug dogs that cannot do the full job, these police departments could find themselves in a pinch soon enough. There is evidence that Congress will begin discussing the legalization of marijuana at the national level in 2019. The second federal reform is pushed through, all the drug-sniffers who detect weed will be out of a job – and the cops shops will be out around $6,000 for every hound they have to retire.