Supporters of decriminalizing marijuana are hoping to build momentum on Capitol Hill after a historic election that saw the politics of pot take center stage in four states. The marijuana industry's public relations campaign has so far been limited to states, especially California, where a ballot initiative to legalize marijuana almost passed in November. But today, the National Cannabis Industry Association, launched in December to represent the interests of legal marijuana growers and distributors, will hold the first congressional lobbying day in the nation's capital, hoping to shore up support for an industry they say could bring billions of dollars in revenue to the government.