[JURIST] Sheriffs from Colorado, Kansas and Nebraska filed a lawsuit [complaint, PDF] Thursday challenging Colorado’s recreational marijuana law. The sheriffs are asking the court to strike down Amendment 64, the legislation legalizing the sale of recreational marijuana, and to close Colorado’s licensed marijuana retailers. Plaintiffs argue that the amendment is “preempted by federal law and therefore violates the Supremacy Clause [text] (Article VI) of the United States Constitution.” They also argue that the federal government has the authority to regulate interstate commerce, including that of illicit substances, and that the fact that marijuana has been trafficked out of Colorado effectively categorizes it as a form of interstate commerce. The introduction of the lawsuit states:

If allowed to remain in effect, Amendment 64’s legalization and commercialization scheme will conflict with and undermine the federal government’s careful balance of anti-drug enforcement priorities and objectives. It will permit and enable at least hundreds—if not many thousands—of marijuana cultivation, distribution, sales, and consumption operations.

The legal use and sale of marijuana [JURIST backgrounder] for both medical and recreational purposes has become a controversial issue in the US with a number of states contemplating various legalization initiatives. In December Oklahoma and Nebraska filed a lawsuit [JURIST report] against neighboring Colorado over the new marijuana market. In November voters in Alaska, Oregon and Washington, DC, voted [JURIST report] to legalize recreational marijuana. In September the Pennsylvania State Senate approved [JURIST Report] legislation that would legalize several forms of medical marijuana. In July Illinois Governor Pat Quinn signed [JURIST report] legislation that will allow adults and children suffering from seizures access to medical marijuana. In April the Maryland House of Representatives passed a bill [JURIST report] that would decriminalize the possession of small amounts of marijuana.