“Odor of marijuana” still remains — even in an era of widespread legalization — a favorite method of justifying warrantless searches. It’s an odor, so it can’t be caught on camera, which are becoming far more prevalent, whether they’re mounted to cop cars, pinned to officers’ chests, or carried by passersby.

Any claim an odor was detected pits the officer’s word against the criminal defendant’s. Even though this is a nation where innocence is supposed to be presumed, the reality of the criminal justice system is that everyone from the cops to the court to the jury tend to view people only accused of crimes as guilty.

But this equation changed a bit as states and cities continued to legalize weed possession. Once that happened, the claim that the “odor” of marijuana had been “detected” only meant the cops had managed to detect the odor of a legal substance. The same thing for their dogs. Drug dogs are considered the piece de resistance in warrantless roadside searches — an odor “detected” by a four-legged police officer that’s completely incapable of being cross-examined during a jury trial.

As legalization spreads, courts have responded. There have been handful of decisions handed down that clearly indicate what the future holds: cops and dog cops that smell weed where weed is legal don’t have much legal footing when it comes to warrantless searches. Observing something legal has never been — and will never be — justification for a search, much less reasonable suspicion to extend a stop.

The present has yet to arrive in the Seventh Circuit. Detecting the odor of a legal substance is still considered to be a permission slip for a warrantless search. And that’s only because there’s one weird stipulation in the law governing legal marijuana possession in Illinois.

In this case, a traffic stop led to the “detection” of the odor of marijuana. That led to the driver fleeing the traffic stop and dropping a gun he was carrying. And that led to felon-in-possession charges for Prentiss Jackson, who has just seen his motion to suppress this evidence rejected by the Seventh Circuit Appeals Court.

Here’s how this all started, as recounted in the appeals court decision [PDF]:

The officer smelled the odor of unburnt marijuana emanating from the car. He knew the odor came from inside the car, as he had not smelled it before he approached the vehicle. During their conversation about the license and registration, the officer told Jackson he smelled “a little bit of weed” and asked if Jackson and the passenger had been smoking. Jackson said he had, but that was earlier in the day, and he had not smoked inside the car.

Through the officer’s training, he knew the most common signs of impairment for driving under the influence were the odor of marijuana or alcohol and speech issues. He was also taught to look for traffic violations. Concerned that Jackson might be driving under the influence because of the head and taillight violation, the odor of marijuana, and Jackson’s admission that he had smoked earlier, the officer asked Jackson whether he was “safe to drive home.” Jackson said he was. His speech was not slurred during the interaction, and his responses were appropriate.

Now, I’m not a federal judge. (And probably shouldn’t be one, for several reasons.) But I think I would have immediately called bullshit here. According to the officer’s own statements, his “training” led him to believe things like unburnt marijuana and unlit headlights/taillights are indicators of “driving under the influence.” I would have asked for the officer to dig deep into the reserves of his “training” to explain these assertions. The only one that fits is Jackson’s admission he had smoked “earlier.” And, even with that admission, Jackson cleared the impairment test.

The officer, however, insisted he had probable cause to engage in a warrantless search of the car, based exclusively on his detection of the odor of “unburnt” marijuana. The officer told Jackson he was going to cite him for weed possession (not for the amount, but for how it was stored in the car). He also told the passenger he would make an arrest if Jackson did not “agree” to a “probable cause search.”

Jackson moved to the back of his car as ordered by the officer. Shortly before the patdown began, Jackson fled, dropping a handgun he was not legally allowed to possess.

Jackson challenged the search in his motion to suppress, arguing that marijuana legalization meant an assertion that the odor of a (legal) drug had been detected by an officer meant nothing in terms of probable cause for a warrantless search. The lower court rejected Jackson’s argument. The Seventh Circuit Appeals Court agrees with the trial court.

First, the court says marijuana, while legal in Illinois, is still illegal under federal law. And the suspicion a federal law has been broken (even if it can’t be enforced locally) is still enough to justify further questions and further exploration of a car.

Furthermore, state requirements for transporting legal marijuana in personal vehicles were not met by Jackson’s baggies of personal use weed.

[T]he [Illinois] Vehicle Code […] clearly states that when cannabis is transported in a private vehicle, the cannabis must be stored in a sealed, odor-proof container—in other words, the cannabis should be undetectable by smell by a police officer.”

That’s a really weird stipulation. It basically tells residents that in order to legally transport drugs they must act like drug smugglers. And, while I haven’t seen a case raising this issue yet, one can be sure people have been criminally charged for following the law because officers believe efforts made to prevent officers from detecting drugs is, at the very least, reasonable suspicion to extend a stop or, better yet, probable cause to engage in a warrantless search.

And this is likely why that particular stipulation (which I haven’t seen in other places where weed is legal) was included in this law: it doesn’t remove one of the handiest excuses to perform a warrantless search — the “odor of marijuana.”

The smell of unburnt marijuana outside a sealed container independently supplied probable cause and thus supported the direction for Jackson to step out of the car for the search.

That’s pretty handy… at least for cops. It allows them to “detect” the odor of a legal substance in order to treat it as contraband. And they need to do little more than claim in court they smelled it — something that’s impossible to disprove. Illinois has managed to do the seemingly impossible: it has legalized a substance while allowing law enforcement officers to treat it as illegal. That’s quite the trick. And because of that, it’s still perfectly legal to pretend legal substances are contraband when it comes to traffic stops in Illinois.