Who is the antagonist in Truman by David McCullough?

Truman is the star of the biography, and everyone else is a supporting character. Even great men of the twentieth century like General Dwight Eisenhower, British Prime Minister Winston Churchill, and President Franklin Roosevelt are supporting players in the Truman show.

Other people in the book are either good or bad, depending on Truman's point of view. General Douglas MacArthur is one of Truman's villains because he embarrasses Truman during the Korean conflict and remains so stubbornly insubordinate that Truman has to fire him. On the other hand, Charlie Ross and General George Marshall are "good" because they support Truman in his efforts. They keep him from making quick decisions and saying the wrong thing in public