TL;DR Official definitions of "drug trafficking" and "drug abuse" seem to contradict the U.S. Customs and Border Protection application of the terms, which the agency has used to justify lifetime entry bans for Canadians who admit to using cannabis.
While the Obama administration relaxed the enforcement of this prohibition, however, the Trump administration is uncompromising in its prosecution of marijuana-related offenses. U.S. Attorney General Jeff Sessions, in particular, is notoriously skeptical of the drug, even once reportedly stating that he "liked the KKK until [he] realized they smoked pot."
While the policy of denying admission to drug-using foreigners is longstanding, its enforcement, scope, and widespread publicity appear to have reached unprecedented levels this year.
That's not an accident. The USCBP under Trump is a political tool that serves to bolster the president's claims about immigration and foreign nationals.
Few have questioned the legality of lifetime entry bans for Canadians. But upon close inspection of the Immigration and Nationality Act, which dictates border policies, and the Controlled Substance Act, which guides drug enforcement, the justification for these bans seems baseless.
The Immigration and Nationality Act states that anyone "who is determined... to be a drug abuser or addict" is inadmissable to the United States (Sec. 212. A. iv).
The law further specifies that anyone who "is or has been an illicit trafficker in any controlled substance or in any listed chemical... or is or has been a knowing aider, abettor, assister, conspirator, or colluder with others in the illicit trafficking in any such controlled or listed substance or chemical" may be denied entry (Sec. 212. C. i).
The key terms here are "drug abuser" and "illicit trafficker."
The U.S. recognizes the definition of "illicit trafficking" specified in the Single Convention of Narcotic Drugs through the United Nations. The convention states that "'illicit traffic' means cultivation or trafficking in drugs contrary to the provisions of this Convention."
Specifically, this definition points to an intent to grow and sell cannabis. In Article 14, the convention further distinguishes between "traffic in" and "consumption of drugs."
But "drug abuser" is the charge most frequently levied against marijuana-using travellers.
The official definition of "drug abuse" is more ambiguous than "trafficking." The Controlled Substances Act (CSA), however, seems to differentiate between occassional or one-time consumption of a drug and the physical effects or addiction that would qualify "abuse."
A common refrain in the CSA is "potential for abuse" (Section 802.9.D, for example), which seems to indicate that the law defines "abuse" as a mode of frequent consumption that has definite adverse consequences. In other words, casual, occassional cannabis use does not seem to meet the requirements of "abuse."
Thus, accusations of "drug abuse" at the U.S. border without evidence of drug-related convictions may be unfounded.
Of course, the application of these terms is entirely a matter of interpretation. The USCBP is not acting in direct violation of written law when its agents ban for life Canadians who admit to marijuana consumption.
But this interpretation of legal terms could present the possibility of a court challenge to USCBP enforcement.
In the meantime, learn more about cannabis in Canada with this video: