MacArthur is a major figure in US military and diplomatic history. He played a vital role in the Pacific theater of World War II and commanded UN forces during the Korean War. After Japan's surrender in 1945, MacArthur worked to rebuild the devastated nation, drafting a new Japanese constitution and helping to establish a democratic government. Many viewed MacArthur as a hero, but he was suddenly relieved(解雇する)of his duty by President Truman at the height of the Korean War.