The Would-Be Philosopher-King

On the night of May 2, 2011, Michael Ignatieff, leader of the Liberal Party of Canada, was huddled in a Toronto hotel suite to await election results. It was nearly six years since he had left Harvard University and, at the age of 58, transformed himself into a politician, despite having no proven political skills and living outside his native Canada for the previous 30 years.

A historian by training, Ignatieff is something of a serial self-reinventor. He jettisoned a career in academe in the mid-1980s and became, by turns, a screenwriter, essayist, columnist, memoirist, BBC television host, biographer of the philosopher Isaiah Berlin, Booker shortlisted novelist (Scar Tissue), war correspondent, and authority on ethics and international affairs. For 16 years he was that rarest of things, a nonacademic public intellectual—or as the Oxford political philosopher Alan Ryan once described him, a "public moralist." Then, in 2000, Harvard beckoned—"picked me out of a lineup," he says, to become a professor of human rights at the John F. Kennedy School of Government. His success looked effortless....