When medical-marijuana dispensaries open in the District this spring, US Attorney Ron Machen will find himself in a complicated situation. Unlike US Attorneys in the 50 states, DC's top lawman is charged with enforcing local law in addition to federal. Though selling medical marijuana has been legalized in DC, it's still a federal crime, putting Machen's federal and local duties at odds.

In California and Colorado, where medical marijuana is legal under state law, federal prosecutors have cracked down on dispensaries. Machen hasn't said how he'll handle the sale of pot here, and his office declined to comment. But if he does enforce the federal law, he may run into trouble. Though the legislation that legalized pot in DC wasn't put to a popular vote, residents have voted overwhelmingly in the past in favor of legalizing medical marijuana. Getting a DC jury to shut down a dispensary could be tough. Not to mention the PR problems: Coming across as a fed overruling DC law wouldn't sit well with a lot of local residents.

Other drugs are illegal under federal law but legal under DC law, such as the club drug GHB, which can lead to death. But it's hard to compare marijuana with GHB, which isn't nearly as popular as pot or as controversial. "That GHB is not illegal under DC law wouldn't have imposed even a speed bump to federal prosecution," says Jeffrey Taylor, who was DC's US Attorney from 2006 to 2009. Dealing with medical marijuana, on the other hand, he says, "is going to be very tricky for the US Attorney."

This article appears in the April 2012 issue of The Washingtonian.