Federal courts have repeatedly ruled that the smell of marijuana is evidence of criminal activity and justifies a law enforcement search. However, in response to changes in marijuana’s legal status, some state courts are reconsidering whether the smell of marijuana can justify government intrusions and in what circumstances. Over the past 20 years, half of the state has enacted laws, legalizing adults to purchase and use marijuana for recreational purposes. Also, in about 45 states and territories, adults can use marijuana for medical purposes.
Search based on marijuana smell
The Michigan Supreme Court was recently held Peoplev. Armstrong That the smell of marijuana alone does not justify a car warrantless search. in Armstrongpolice surrounded the parked car based on one officer’s report that she smelled marijuana coming from the car. Jeffrey Armstrong was in the passenger seat. The officers pulled him out of the car, searched under the seat and found a gun. Armstrong was charged with illegally carrying a gun. In a pretrial move to suppress the gun, he claimed it was a fruit for both an unconstitutional attack and an unconstitutional search: the attack was illegal because the smell of marijuana did not establish a reasonable suspicion of criminal activity, he said. crime.
The government retorted that the smell of marijuana provided both a reasonable doubt that justified the seizure of the car and its residents, and a possible cause that could justify searching for cars under the so-called automobile exceptions of warrant requirements. The exception to motor vehicles allows law enforcement to search for vehicles without a warrant if there is a cause that could believe they contain contraband or evidence of a crime.
The Michigan Supreme Court refused to debate the government and found that the officer’s claim that the smell of marijuana coming from a parked car did not establish any possible causes that could justify a warrantless search based on the exception of the car. The court did not reach the question of whether the smell provided officers with reasonable doubts detaining Armstrong.
According to a court decision, the 2018 voter-initiated law stated that it is legal for adults over the age of 21 to own and transport marijuana to people or vehicles. “In light of voters’ intentions to legalize marijuana use and possession, the smell of marijuana standing alone no longer constitutes a sufficient cause to support a search for contraband,” the court wrote, finding that the 2018 law held that marijuana alone could establish a possible cause of supplemental odors. The court emphasized that the possible causes of searches depend on the overall nature of the situation and whether law enforcement can demonstrate reasonable possibilities.
Armstrong The court explained that, in combination with a driver who appears to be drunk, the smell of marijuana could establish a cause that could lead to believe he is driving under the influence of marijuana in violation of state law. Similarly, marijuana smell, combined with smoke observation, can establish a cause that could lead to people who might believe they are smoking marijuana in public places. In both cases, police need more than the smell of marijuana to establish a possible cause of the crime.
Colorado State Courts, Illinois, Minnesota and Pennsylvania have taken a similar approach, acknowledging that marijuana smell is not the only factor in determining whether the wholeness of the situation establishes a possible cause for searching.
In Michigan, the notion that marijuana smell alone does not establish a probable cause is not entirely new. Before legalizing the use of recreational marijuana in 2018, Michigan allowed citizens to own and use marijuana for licensed medical purposes. During that time, Michigan’s Court of Appeals addressed a similar question: whether the smell of marijuana established a possible cause for searching for vehicles of drivers who were legally permitted to own marijuana under the Michigan Medical Marijuana Act. If an officer smells marijuana and denied that the driver (who had medical marijuana permission) had marijuana in his car, the court concluded there was a possible cause for the vehicle to be searched. The court reasoned that it was legal for drivers to own marijuana within the law, so it was not just the smell of marijuana that established the possible causes. Rather, the driver lied about having marijuana that established a cause that could have believed he was carrying marijuana in ways or amounts beyond what was allowed.
In jurisdictions where marijuana possession is legal for medical or recreational use, courts must reevaluate the relationship between the smell of marijuana and alleged misconduct. In states like Michigan, where citizens are legally owned and can openly transport marijuana to their cars, smells alone do not suggest illegal activity. In contrast, in states like Illinois, where marijuana in vehicles must be stored in sealed, odorless containers, the smell of marijuana suggests that marijuana is not stored as required by law. There, the smell may support a possible cause.
Long-running legal questions
Courts must address a variety of other questions when Congress decriminates or legalizes marijuana. Many states have not yet determined whether the smell of marijuana provides reasonable doubts about a termination of investigation. under Terryv. Ohiopolice can temporarily detain a citizen based on a reasonable and specific suspicion that the person is involved in a criminal act. in Armstrongthe Michigan Supreme Court considered this question but ultimately did not reach it because there was no need to resolve the case. A few states that addressed this question often dealt with it with determination of possible causes and believe that marijuana smell is one factor and can establish reasonable doubt. Several states have enacted laws banning them, including Arizona and Maryland. Terry Stop based solely on the smell of marijuana.
Some state courts are working on whether there are alleged marijuana-related civil violations. Terry Stop or search considering that the act is no longer defined as a criminal act. For example, the Massachusetts High Court held that, as marijuana is decriminalized in Massachusetts, the smell of burnt marijuana cannot establish a reasonable suspicion of criminal conduct. The Michigan Supreme Court will hear verbal debate next month about whether the car exception allowed troopers to search for cars they learned to smell marijuana and are under the age of 21.
The legalization of marijuana also raises questions regarding the use of drug-detecting dogs. Historically, federal courts did not consider the use of drug detection dogs to be a search. Searches arise when governments infiltrate areas where individuals have reasonable expectations of privacy. Federal courts explain that drug detection dogs are trained to warn against illegal drugs, and that people do not have reasonable expectations of privacy for the scent of illegal drugs. However, many drug detection dogs are trained to detect marijuana. Where the state legalizes marijuana, does the use of these dogs constitute a search? In October, the Tennessee Supreme Court heard oral debate on similar questions. How does hemp legalization affect causal analysis where law enforcement may rely on positive warnings from drug detection dogs that cannot distinguish between legal hemp and illegal marijuana smells?
in Colorado vs McKnightThe Colorado Supreme Court has determined that drug detection dogs trained to warn them to smell marijuana will invade their privacy rights in light of state laws that legalize the possession and transport of small amounts of marijuana. Therefore, drug detection dogs may only be used in Colorado where law enforcement agencies may believe that they contain illegal drugs.
The terms of probation may also be ripe for lawsuits. Recently, the Michigan Supreme Court granted leave to consider whether laws requiring all federal laws require trial courts to prohibit the use of marijuana as permitted by Michigan law. The court also asked the parties to take action in any circumstances whether, alternatively, the court could prohibit the use of marijuana as a condition of voluntary probation.
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Search and seizure jurisprudence may not be phased along with laws that legalize marijuana. Practitioners in these jurisdictions should consider challenging government searches, halts and other actions regarding the smell, possession and use of marijuana. As criminal law changes, the scope of unreasonable government intrusions will also change.
Maya Menlo is an assistant defender for the Michigan Department of Appeals and represents children and adults appealing from juvenile and criminal court cases.
Erin Van Campen is a research and training attorney for Neighborhood Defender Services in Detroit, providing on-call assistance and training to public defenders and appointed attorneys in Wayne County, Michigan.
Together, they teach criminal lawsuits at Wayne State University Law School.
Suggested Quote: Maya Menlo & Erin Van Campen, Legalization of Marijuana State is changing search and seizure jurisprudencesᴛᴀᴛᴇcᴏᴜʀᴛrᴇᴘᴏʀᴛ (September 24, 2025), https://statecourtreport.org/our-work/analysis-opinion/state-legalization-marijuana-changing-changure-jurispudence
