Brookings: “As states legalize marijuana, more marijuana businesses are opening across the country. An obscure 1982 brainchild of Bob Dole’s Senate Finance Committee, section 280E of the federal tax code, is hitting state-legal marijuana sellers in the pocketbook—right now. 280E, which says taxpayers cannot deduct costs of selling federally illegal drugs, is not just helping fund the federal government. It’s also hampering marijuana advertising and marketing—to the satisfaction of nervous parents, and to the consternation of profit-seeking marijuana promoters. 280E was more a political statement than a model of tax policy, and it can’t eliminate marijuana advertising. But it does discourage that advertising, so it may be one of the most useful marijuana tax laws we can imagine. And while some anti-advertising proposals run afoul of the commercial free speech doctrine, 280E is constitutional. So 280E may help slow down Big Marijuana. If so, an anti-advertising tax rule like 280E might come in handy if the public ever musters the strength to take on Big Alcohol and Big Tobacco.