Five years ago the U.S. Supreme Court refused to endorse a principle that could have allowed any cop with a dog to search any home. The court ruled that deploying a drug-detecting canine at the doorstep of a suspected marijuana grower's house in the hope of obtaining probable cause for a warrant (which requires nothing more than a claim that the dog "alerted") itself constitutes a search under the Fourth Amendment.

But what if a cop without a dog claims his own nose detects marijuana inside a home? In that case, the Kansas Supreme Court recently ruled, the alleged odor provides probable cause for a search, which the cop can execute without waiting for a warrant if he says he was afraid the contraband he thought he smelled might be hidden or destroyed in the interim. In practice, the 4-to-3 decision, issued on December 7, gives police carte blanche to search any home at will.

If you doubt that characterization, consider the dubiousness of the odor that supposedly justified a search of Lawrence Hubbard's apartment. Lawrence, Kansas, police officer Kimberly Nicholson followed Hubbard home after mistaking him for someone with an arrest warrant. As Hubbard exited his apartment to clear up the misunderstanding, Nicholson testified, she "smelled a strong odor of raw marijuana emanating from the apartment." She claimed she was standing about two feet from the front door, while Hubbard said it was more like six or seven feet.

What police ultimately discovered was 25 grams (less than an ounce) of marijuana, which was inside a sealed plastic container, inside a locked safe, inside a bedroom closet about 30 feet from where Nicholson was standing. The cops also found "a small amount of marijuana on a partially burnt cigarillo in the living room," which would have smelled like burnt marijuana, not "raw marijuana" (by which Nicholson presumably meant cured marijuana, as opposed to growing or freshly harvested plants). Another officer, Ronald Ivener, nevertheless testified that he also smelled "raw marijuana" while standing outside the apartment, an odor he described as "potent" and "overwhelming."

You might speculate that Nicholson caught a whiff of the cigarillo as Hubbard opened his door and confused the smell of burnt marijuana with the smell of "raw marijuana." But that hardly seems possible in light of Nicholson's extensive training and experience. "As part of her law enforcement training and while in her official capacity," the trial judge noted, "Officer Nicholson has detected the smell of raw marijuana 200 to 500 times and burnt MJ 100 to 300 times." So either she was exaggerating her ability to distinguish "raw marijuana" from burnt marijuana by odor, or she was asserting a superhuman (and maybe even supercanine) ability to detect Hubbard's triply contained stash from a distance of 30 feet.

Nor was that the only dubious claim that Nicholson made to justify entering Hubbard's home without a warrant. Looking through his window, she said, she saw "five to seven people." She and her colleagues ordered Hubbard's guests to leave. Notably, "the officers testified they did not smell marijuana on anyone as they were leaving," meaning that the source of the "raw marijuana" odor must have remained in the apartment. While waiting for a warrant, Nicholson et al. "did a security sweep to make sure no one remained in the apartment." It was during this "security sweep" that the officers found the cigarillo, along with "several bongs, which were clean and had no marijuana residue." They also noticed Hubbard's safe.

The police argued that the "security sweep" was necessary to protect officer safety and prevent the destruction of evidence. A state appeals court rejected the first rationale, noting that "it is limited to warrantless sweeps incident to a lawful arrest." The court also found that "the officers failed to articulate specific facts that reasonably warranted a belief that anyone in Hubbard's apartment posed a danger to the officers or others." But the appeals court was persuaded by the second rationale, the fear that someone would flush the marijuana that Nicholson and Ivener claim to have smelled down a toilet. The appeals court concluded that the alleged odor provided probable cause to believe a crime had been committed, while "the officers' perceived need to preserve evidence" of that crime constituted an "exigent circumstance" that justified searching the apartment without a warrant.

The Kansas Supreme Court concurred. "We agree with the lower courts that the facts as found by the district court established probable cause to believe contraband would be found inside the apartment," the majority opinion says. "We further hold an exigent circumstance—the need to prevent evidence destruction—supplied an exception to the warrant requirement that permitted the officers to search the apartment for individuals who might have been remaining within it."

After the warrant was issued, the cops opened Hubbard's safe and found what the court describes as "25.07 grams of raw marijuana inside a Tupperware container." Hubbard received two 12-month sentences for possession of marijuana and possession of drug paraphernalia, both misdemeanors, and was granted probation. While we should by no means dismiss the cost of Hubbard's arrest and prosecution, or the lingering collateral consequences of those convictions, the implications of this decision for the privacy of other Kansas residents are at least as troubling, notwithstanding the court's assurances.

"We hold that the totality of the circumstances surrounding a law enforcement officer's detection of the smell of raw marijuana emanating from a residence can supply probable cause to believe the residence contains contraband or evidence of a crime," the Kansas Supreme Court says. "Such circumstances include, but are not limited to, proximity to the odor's source, reported strength of the odor, experience identifying the odor, elimination of other possible sources of the odor, and the number of witnesses testifying to the odor's presence. This is ultimately a case-by-case determination based on the circumstances. Not all cases relying on odor will have the same result."

But if the utterly implausible odor claim in this case provides probable cause, so does any such claim. And if the possibility that evidence will be destroyed, which is always a concern in drug cases, counts as an emergency justifying a warrantless search, no one's home is safe from such invasions.

[Thanks to Walter Olson for the tip.]