[JURIST] Oklahoma and Nebraska filed a lawsuit [complaint, PDF] against neighboring Colorado on Thursday over the new marijuana market, claiming the state-regulated recreational marijuana shops are piping marijuana into neighboring states [NYT] where marijuana is illegal. In the lawsuit, filed directly with the US Supreme Court [official website], the two states are also claiming that legalized marijuana violates the Supremacy Clause [text] of the US Constitution. The lawsuit contends that allowing Colorado to continue with its state-run marijuana shops is in direct conflict with federal law and the Supremacy Clause, and is therefore unconstitutional. Neighboring states claim they have seen an increase of marijuana entering their towns since recreational sales began in January. Colorado Attorney General John Suthers [official website] stated [press release] that he will “vigorously defend” the law.

The legal use and sale of marijuana [JURIST backgrounder] for both medical and recreational purposes has become a major political issue in the US with a number of states contemplating various legalization initiatives. Voters in Alaska, Oregon and Washington, DC, voted [JURIST report] in November 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.