Nebraska and Oklahoma filed the first major court challenge to marijuana legalization, saying that Colorado’s growing array of state-regulated recreational marijuana shops was piping marijuana into neighboring states and should be shut down. The lawsuit asks the United States Supreme Court to strike down key parts of a 2012 voter-approved measure that legalized marijuana in Colorado for adult use and created a new system of stores, taxes and regulations surrounding retail marijuana. (See also: Colorado vows to defend pot law against states' challenge)