On the morning of February 26, Washington, D.C., became the newest frontier in the national movement for legalizing recreational marijuana. Adults in the district can now possess two ounces, grow up to six plants, and share their crop yields with others—but it’s not yet legal to buy or sell the drug.

D.C. follows Colorado, Washington and Alaska in legalizing pot. But policymakers in those states are still working out regulatory structures, and, under federal law, marijuana remains a Schedule 1 narcotic. That makes using it a federal crime. D.C. Mayor Muriel Bowser says that doesn’t matter, though, because the people of the District favor legalization: “We would encourage the Congress to not be so concerned with overturning what 7-in-10 voters said should be the law in the District of Columbia,” she said at a February 25 conference.

House Republicans say the voter approval is inconsequential and that Bowser could face prison time for the initiative. The District of Columbia is under Congress’s jurisdiction, so any legislation must be submitted to Congress for approval. In December, Congress passed a spending bill for D.C. that included a provision banning the legalization of marijuana. This bill makes D.C.’s new pot laws illegal. “[T]oday we have one Washington against the other,” the New York Times wrote of the conflict.

Concern abounds not just over the contradiction between federal and regional laws, but also over D.C.’s failure to open up legal channels to buy and sell cannabis. In the absence of customary commerce, a social economy is expected to take root. And aspects of the illegal trade will inevitably be seedy. “People are going to rush into the breach here and try to take advantage,” says Allen St. Pierre, executive director of the National Organization for the Reform of Marijuana Laws. “And some will not do it right.”

Twenty-seven U.S. states have either decriminalized pot possession or legalized medical use. With the nation’s capital now on board, the movement for legalizing recreational use will likely accelerate. For more on this trend, read “What Can Sharks and Jellyfish Teach Us About Marijuana and President Obama?”