The Supreme Court declined on Monday an effort by Nebraska and Oklahoma to have Colorado’s marijuana legalisation laws which permit adults to buy, sell or use an ounce of the drug approved in a ballot initiative by Colorado voters in 2012.
The court declined to hear an unusual lawsuit by Nebraska and Oklahoma, which said that marijuana is being smuggled across their borders and noted that federal law still prohibits the drug.
Two conservative justices, Clarence Thomas and Samuel Alito, said they would have heard the case.
Colorado stands by its law. It noted that the Obama administration has indicated the federal government lacks the resources and inclination to enforce fully the federal marijuana ban.
"The fact remains - Colorado marijuana continues to flow into Oklahoma in direct violation of federal and state law," Oklahoma Attorney General Scott Pruitt said after the court's action.
Colorado should stop refusing to take reasonable steps to prevent the flow of marijuana outside of its borders and the Obama administration should enforce federal law against marijuana, Pruitt added.
Tom Angell, chairman of the Marijuana Majority advocacy group favoring marijuana legalisation, welcomed the court's action.
"At the end of the day, if officials in Nebraska and Oklahoma are upset about how much time and resources their police are spending on marijuana cases, as they said in their briefs, they should join Colorado in replacing prohibition with legalization," Angell said.
"That will allow their criminal justice systems to focus on real crime, and it will generate revenue that can be used to pay for healthcare, education and public safety programs," Angell added.