If the law passes, D.C. will join the 17 other states that have already decriminalized the drug. D.C. Delegate Eleanor Holmes Norton has also warned that "If Members try to interfere... I will stoutly defend D.C.’s right to pass such legislation."
The mayor and city police chief both support maintaining penalties for public smoking, but at $25, the fine for pot will be lower than most city parking tickets.
There's still some concern that racial disparities among those arrested for smoking will persist, some advocates have said.
House Speaker John Boehner has said he's certain Congress will look at the law.