The aff violates the international law (UN 1961 Single Convention on Narcotic Drugs).

Under the United Nations 1961 Single Convention on Narcotic Drugs, signatories agreed to exclusively allow medical and scientific uses of the listed drugs, including marijuana.[2] This includes the production, export, import, distribution of, trade in, and possession of marijuana.[3] This Convention also created the International Narcotics Control Board, a quasi-judicial body which is responsible for monitoring and supporting signatory countries’ compliance with the international drug treaties.[4] Under the plain language of the convention, federal legalization of adult use marijuana would violate this commitment, and the International Narcotics Control Board has already voiced their disapproval of the U.S. federal government’s decision to allow the states to legalize adult use.[5]

International law certainly influences national and local laws through good faith compliance, but the bigger and more applicable question here is whether international law can influence a national government enough to refuse their citizens popular policy changes. This is entirely dependent upon the consequences the country would face if they were to violate the international law.