For the time being, individual marijuana users in Colorado and Washington State, which voted to legalize recreational use of pot, should be "well insulated" from federal authorities, University of Denver law Prof. Sam Kamin tells CBS News. "The federal government still criminalizes a lot of that behavior but has said it's not interested in individual users," he says. The federal government can't force states to criminalize marijuana use.
What it can do is charge that Colorado's or Washington state's retail provisions conflict with the Controlled Substances Act -- that's essentially the tactic the feds used to sue Arizona over immigration, Kamin explained. "While they couldn't force Arizona to enforce immigration laws, they could sue against provisions in direct conflict with it," he said. In addition to suing the states, the federal government could threaten to withhold state funding to state and local law enforcement until they enforce federal laws. It could also make life difficult for marijuana retailers through the IRS or other legal outlets.