ABC's Barbara Walters tried to get some clarity from Barack Obama about his administration's attitude to the curious fact that starting next year marijuana will be legal in Colorado and Washington but not in the United States of America. His answer that "it would not make sense for us to see a top priority as going after recreational users in states that have determined that it’s legal" because "we’ve got bigger fish to fry" has a lot of people excited. But I think there's less to this than meets the eye.
For starters, as Alex Seitz-Wald notes there have been a lot of broken promises from the administration regarding marijuana policy in California already. To offer what I think is a generous construal of the situation, the federal law enforcement apparatus unwisely includes an entire agency—the Drug Enforcement Administration—whose entire raison d'être is to prosecute the war on drugs. As a matter of institutional culture, getting the DEA to back off is like trying to get a dog to not run after squirrels. The DEA is under the president's authority, but to shift that culture you'd really have to throw your back in it and weather some fights in the press and on the Hill and the White House simply doesn't care to do anything other than let the drug war operate on autopilot.
Meanwhile, back to Colorado and Washington. The simple fact of the matter is that the DEA doesn't remotely have the resources to target, arrest, and prosecute recreational marijuana users. But Colorado and Washington didn't legalize recreational marijuana use. They set up a framework for legal marijuana cultivation, for marijuana processing, and for wholesale and retail sales of marijuana.
The DEA doesn't have the resources to target a guy for sharing a bowl with his friends, but they certainly do have the resources to target a large marijuana farm or a fixed-location marijuana retailer trying to establish a legal business. What's more, they have the resources to arrest and prosecute state officials who involve themselves in the licensing and permitting for legal marijuana businesses. Given resource constraints, these are in fact exactly the bigger fish that the DEA has to fry that would make it unreasonable for them to be worried too much about recreational use. The actual question on the table isn't whether the federal government is going to be able to replace state and local law enforcement, the question is whether the federal government will do everything in its power to subvert the new frameworks in CO and WA. The president's statement to Walters is entirely consistent with a posture of maximum subversion.