If you had to describe the century's geopolitics in one sentence, it could be a short one: Freedom won. Free minds and free markets prevailed over fascism and communism.
So a more suitable choice would be someone who embodied the struggle for freedom: Franklin Roosevelt, the only person to be TIME's Man of the Year thrice (for 1932, 1934 and 1941). He helped save capitalism from its most serious challenge, the Great Depression. And then he rallied the power of free people and free enterprise to defeat fascism.
Other great leaders were part of this process. Winston Churchill stood up to Hitler even earlier than Roosevelt did, when it took far more courage. Harry Truman, a plainspoken man with gut instincts for what was right, forcefully began the struggle against Soviet expansionism, a challenge that Roosevelt was too sanguine about. Ronald Reagan and Mikhail Gorbachev helped choreograph the conclusion of that sorry empire's strut upon the stage. So too did Pope John Paul II, a Pole with a passion for both faith and freedom. And if you were to pick a hero who embodied America's contribution to winning the fight for freedom, it would probably be not Roosevelt, but instead the American G.I.