Less than one week after D.C. allowed marijuana legalization to go into effect (against the wishes of vocal Republicans in Congress), the D.C. Council unanimously passed emergency legislation Tuesday to ban marijuana use at nightclubs and other places of business, even during private events.

The measure, which D.C. Mayor Muriel Bowser sent to the council the day the city began observing legalization, is intended to curb the establishment of membership-based clubs and other arrangements that could lead to unregulated commercial activity in the District. D.C. currently faces some big questions about marijuana's future, including if and how the city would ever be able to tax or establish a legal marketplace, since Congress forbid funding such activities in a federal budget bill passed in December.

Critics, including Adam Eidinger, head of the D.C. Cannabis Campaign, believe that the law established by Initiative 71, which voters approved in November, should be sufficient. He thinks that Bowser's new rules go...