Martin Walker's critical biography of Bill Clinton focuses on the president as a classic figure of America's post-World War II meritocracy, a poor boy from the segregated old South who won scholarships to elite universities and became a lawyer fascinated by the process and the power of government.??Walker also unearths a private life that has resonated to the rhythmic clich?s of a country-and-western song:??Clinton's father died in a car wreck before...