Harry Truman

33rd American President who made the decision to drop atomic bombs on Hiroshima and Nagasaki, launched the Marshall Plan, created NATO, and oversaw the beginning of the Cold War — a small-town Missouri politician who became president without preparation when FDR died and made some of the most consequential decisions in modern history.

Demonstrates that leadership is often about making impossible decisions with incomplete information under time pressure — Truman's decision to drop the atomic bombs, controversial ever since, was made in the belief that it would save more lives than a land invasion — and the Marshall Plan demonstrated that magnanimity toward former enemies can create lasting peace.