Niebuhr debated Charles Clayton Morrison, editor of "The Christian Century" magazine, about America's entry into World War II. Morrison and his pacifistic followers maintained that America's role should be strictly neutral and part of a negotiated peace only, while Niebuhr claimed himself to be a realist, who opposed the use of political power to attain moral ends. Morrison and his followers strongly supported the movement to outlaw war that began after World War I and the Kellogg–Briand Pact of 1928. The pact was severely challenged by the Japanese invasion of Manchuria in 1931. With his publication of "Moral Man and Immoral Society" (1932), Niebuhr broke ranks with "The Christian Century" and supported interventionism and power politics. He supported the reelection of President Franklin D. Roosevelt in 1940 and published his own magazine, "Christianity and Crisis". In 1945, however, Niebuhr charged that use of the atomic bomb on Hiroshima was "morally indefensible".