Buried in February's $956 billion farm bill is an amendment ... that legally distinguishes industrial hemp from marijuana, after decades of conflation [of the two]. It defines hemp as an agricultural crop rather than a drug - and effectively frees American farmers to grow it for the first time in almost 60 years. For 20 years, legislators, farmers, hippies, activists, agency heads and agronomists have worked to recast hemp as a game-changer, an American cash crop that could jump-start the country's next economic revival. Colorado, Vermont and Kentucky wasted no time launching their industrial hemp research and the pilot programs provided for in the farm bill. In an obscure notice dated April 16th, the USDA alerted state and county officials that farmers in states that [approved] hemp production (15 so far) could now include hemp acreage in their crop reports. The floodgates have opened. The current American hemp market is estimated at nearly half a billion dollars, with hemp's oil, seed and fiber used in food, carbon-negative building materials, and automobile composites that are already inside millions of cars. Hemp cultivation is ... as old as the country itself. George Washington and Thomas Jefferson grew it, hemp was once legal tender, and several drafts of the Declaration of Independence were written on hemp paper. During WWII, American farmers were paid to grow it, cultivating more than 150 million pounds of industrial hemp to support the American war effort.