With virtually no questions asked, an undercover ABC News team was able to purchase a half ton of one of the world's most dangerous bomb-making materials and move it into a storage shed only a few miles from the White House and the U.S. Capitol. Despite its use in the bombing of the Oklahoma City Federal Building, there are still no federal laws restricting the purchase of ammonium nitrate, a chemical fertilizer, widely sold at farm supply stores. The ABC News undercover team made the purchases, in cash, at farm supply stores in North Carolina and Virginia and were never...