The 2018 Farm Bill defines hemp as "The plant Cannabis sativa L. and any part of that plant whether growing or not, with a delta-9 tetrahydrocannabinol [TH] concentration of not more than .3 percent on a dry weight basis." It is important to compare the definition of hemp with the definition of marijuana. Marijuana is defined by the Controlled Substances Act as "the plant Cannabis sativa L., whether growing or not." The 2018 Farm Bill expressly amended the Controlled Substances Act definition of marijuana to exclude the definition of hemp. Practically speaking, what this means is that marijuana is now the plant Cannabis sativa L., whether growing or not with a TH concentration of more than .3 or percent.
So why does it matter that hemp, which is legal federally, has a TH concentration of .3 percent or less, and marijuana, which is illegal federally, has a TH concentration of more than .3 percent? The legalization of hemp now gives practitioners a new mechanism by which to challenge searches that begin when a dog has alerted to the scent of marijuana. In 2005, the U.S. Supreme Court held in Illinois v. Caballes, 543 U.S. 405 (2005), that dog sniffs do not expand the scope of a traffic stop and that they are not searches under the meaning of the Fourth Amendment because dog sniffs do not intrude upon a legitimate privacy interest as outlined under Katz v. United States, 389 U.S. 347 (1967). The Caballes court went on to reason that this decision was consistent with Kyllo v. United States, 533 U.S. 27 (2001) because the legitimate expectation that information about perfectly lawful activity will remain private is entirely different from hopes or expectation that contraband will not be detected. Caballes, at 410.
At this point in time, there is no research to suggest that dogs are able to distinguish between hemp, a legal substance, with TH concentration of .3 percent or less and marijuana, an illegal substance, with TH concentration of .3 percent or more. A dog, when it alerts, is simply alerting to the presence of possible TH. The dog has no ability to determine if the substance is legal hemp with a concentration of .3% or less. Now that the mere presence of an alert does not necessary mean that a defendant is engaged in non-lawful activity, the Caballes decision must be revisited. The Court in Caballes specifically stated that there is a difference in a privacy expectation when it is based on lawful activity.
Practitioners with dog-sniff cases involving marijuana should challenge these searches. First, practitioners should make sure that the lab results show a TH concentration of more than .3 percent to ensure the substance is in fact marijuana. Secondly, practitioners should file motions to suppress raising this issue. At the evidentiary setting on the motion to suppress, practitioners should cross-examine the officer on the dog's ability to differentiate between concertation levels of TH and any training records the dog may have the correlate with differentiation of TH concentration levels.
