After losing at the ballot box and in the court of public opinion, marijuana opponents are turning to the federal judiciary in an attempt to halt the momentum of marijuana legalization efforts happening at the state level. But legal experts say that plaintiffs in a series of lawsuits brought against the state of Colorado for its marijuana regulation regime face slim chances of succeeding — if the courts agree to hear them at all.

The attorneys general of Nebraska and Oklahoma kicked off the legal attacks in December. They’re arguing that Colorado’s law violates the Controlled Substances Act, which dictates federal drug policy. Their lawsuitcontends that “the State of Colorado has created a dangerous gap in the federal drug control system enacted by the United States Congress. Marijuana flows from this gap into neighboring states, undermining Plaintiff States’ own marijuana bans, draining their treasuries, and placing stress on their criminal justice systems.”

Under the Supremacy Clause of the Constitution, the CSA takes precedence over Colorado’s state law if the two are in conflict as the plaintiffs argue. Colorado says weed is legal, but the CSA says it isn’t. Open-and-shut case, right?

Actually, no. “The regulatory regime that Colorado has put in place is notpreempted by the Controlled Substances Act,” legal professor Sam Kamin, who was part of the task force implementing Colorado’s marijuana laws, said in an interview. “I expect those claims to fail.” The issue? The Controlled Substances Act dictates federal drug policy — but it in no way compels states to enforce that policy. [Read more at The Washington Post]