For the group Mothers Against Drunk Driving (MADD), the drinking age recently questioned by college presidents, is not a topic for debate. In August the organization publicly berated the Amethyst Initiative, a group of 100 presidents and chancellors who signed a statement urging legislators to revisit the law and to examine its effectiveness. The confrontation revealed the difference between two views of the same problem. MADD has long cast under-age drinking in black-and-white terms; many college officials see it as impossibly gray. Although the letter drew the ire of several legislators and national newspapers, the man behind the document has not retreated. In October, John M. McCardell Jr., a former president of Middlebury College, moved his fledgling nonprofit group, Choose Responsibility, from Vermont to Washington, D.C. There, he hopes to do just what MADD did: Start a movement that changes not only laws, but how Americans think about alcohol and young adults.