EVENTS ARE CONVERGING TO ELEVATE the nuclear crisis with Iran into the central crisis of the Bush presidency. War presidents are graded not by circumstances they inherit, including those that lead to war. They are judged by how they react to those circumstances.Franklin Roosevelt as a war president is defined not by the attack on Pearl Harbor, but by the radical war aim he laid out against Japan and Germany in the wake of Pearl Harbor--unconditional surrender--and by his relentless and successful pursuit of that war aim until the day he died.When Lyndon Johnson became president in November 1963, he...