Olivia Phelan Heiser, Let Slip the Dogs of Drug War: Law Enforcement Canines Do Not Fall Under the “Only-Contraband” Exception, 2024 Wis. L. Rev. 1937 (2024).
The 2018 Farm Bill removed hemp from the Schedule I list of the
Controlled Substances Act. This legal change caused law enforcement
agencies and courts to reanalyze assumptions made in routine investigation
tactics and prior caselaw. Some law enforcement agencies still use marijuanatrained
canines. Previous Supreme Court cases have held that a sniff by a law
enforcement canine is not a Fourth Amendment search because these canines
detect only contraband. But marijuana-trained canines cannot detect a
difference between hemp and illicit marijuana. Because these canines no
longer detect only contraband, the “only-contraband” exception should no
longer apply—a canine sniff is a search that requires probable cause.
In United States v. Deluca, the Tenth Circuit held that, even in light of
the 2018 Farm Bill, a law enforcement canine can still support probable
cause. But Deluca did not grapple with Supreme Court precedent explaining
when use of a sense-enhancing technology constitutes a search requiring
probable cause. Even though the opinion was unpublished, subsequent
opinions in other jurisdictions cite Deluca to conclude the question has been
asked and answered. Deluca overlooks key reasoning from Supreme Court
jurisprudence on canine sniffs and must be carefully analyzed to prevent it
from metastasizing in other circuits.
Similarly, in United States v. Plancarte, the Seventh Circuit held that
a law enforcement canine sniff is not an unreasonable search. Plancarte
emphasized that a canine sniff’s limited intrusiveness does not implicate a
reasonable expectation of privacy. Deluca and Plancarte signal a troubling
shift in the face of advancing law enforcement sense-enhancing technology.
