More history no one wants you to know, because no one comes out looking good.
Cordell Hull, Secretary of State under Franklin Delano Roosevelt, in his Memoirs recounts the plan proposed by certain American Roman Catholics, and probably vetted by the Vatican, for peace between China, Japan, and the United States [pages 991-994]. This Roman Catholic plan, in my opinion, was not a bad plan, and if adopted would have prevented war between the U.S. and Japan. However, in the context of the overall global Catholic Plan for 1941, it appears to be Catholic diplomacy to help insure they would win the war.
Consider the world broken into five great empires in 1941, each oppressive in its own way. The Catholic Empire is usually equated with Adolf Hitler, or the Nazi Party of Germany, and included basically all of Europe, with influence in much of South America. The Communist Empire was mainly the Soviet Union, running from eastern Europe to the Pacific Ocean. By far the largest and most oppressive empire was run by the British, who controlled Great Britain, most of Africa, Australia, Canada, and the Indian subcontinent (now India, Pakistan, Bangladesh, and Burma) and more. The American Empire was confined to the Americas except for the Philippine Islands and Hawaii.
Roman Catholics were making a bid for total global domination, which of course p.o.'d the other empires. Led by Pope Pius XII and Adolf Hitler, having massacred or placed in concentration camps most European atheists, agnostics, Jews, and Protestants (except Lutherans, who were being merged into the Catholic Church in Germany), Catholic armies went plunging into the atheist Soviet Union beginning on June 22, 1941. [See also: Atheist Holocaust]
The Catholics [often called by their political term, Fascists] had long flirted with the government of Japan. Japan was a democracy and not at all Roman Catholic, having repelled Roman Catholic invaders in the late 1500's. However, the government had come to be dominated by a military faction that wanted Japan to copy the other empires by expanding, enabled by a liberal faction that justified expansion by believing they were liberating other Asian nations from domination by Great Britain, France, the United States, and the Netherlands.
Any expansion by Japan could be beneficial to the Catholic military campaign, since it would come at the expense of one of the other empires, with one big old caveat. If America entered the war on the side of the British Empire and the Soviet Empire (who normally were enemies, but were both being attacked by the Catholics), that would make Hitler's job harder.
The Fascist Catholics had a Fifth Column in the United States that had kept the U.S. from declaring war on Germany (and earlier, from aiding the democratic government of Spain when it was attacked by the most Catholic General Franco). Catholic voters were a crucial voting block in the Democratic Party, then the ruling party in the United States. The Catholic Church hierarchy had, on a number of occasions, shown they could influence those voters.
The crew chosen to come up with a peace plan and sell it to the governments of Japan and America consisted of Father Drought, Bishop James Edward Walsh (Superior General of the Catholic Foreign Mission Society) and Postmaster General Frank C. Walker.
The Catholic Peace Plan presented had many dimensions, but the focus was on the old bone China, that had been fought over by international hyenas for over a century. China had been coming under U.S. control due largely to the U.S.-educated Madame Chiang's influence on her husband, Generalissimo Chiang Kai-shek. Chiang acted like a dictator, trying to rule through his Kuomintang Party, but in fact he was simply head of a snarling gang of warlords. The Japanese, trying to restore order and prevent a British-American takeover of China, had staged what eventually became an invasion starting in the 1930's. Chiang's number 2 warlord, Wang Ching-wei, had decided to ally himself with the Japanese and actually ruled a larger, more prosperous territory than Chiang did by 1941. The U.S. Marines, who had helped Chiang when they were not to busy helping American capitalists help themselves to China, were already being withdrawn before superior Japanese strength in 1941, but the U.S. air force was already bombing Japanese
troops under the guise of the American Volunteer Group.
The Plan was really simple. Chiang Kai-shek and Wang Ching-wei would form a joint Chinese government. The Japanese would withdraw their troops and negotiate a peace treaty with the new government. The independence of Manchukuo would be recognized by China and the United States. There would be no large-scale Japanese emigration to China. China would allow for free trade, so U.S. and Japanese commercial interests would be on an equal footing. In addition, the U.S. would end its embargo of Japan.
The immediate problem with the Catholic Plan was that Roosevelt and his crew had long had their eye on the Far East. They already planned go to war with Japan and Germany as soon as the U.S. military was ready. They knew the U.S. economy was ten times as large as Japan's, and they knew the Japanese knew that. Roosevelt could take East Asia when he was ready, as history would prove (although the Japanese fought better and longer than expected).
The Japanese accepted the Catholic Peace Plan. So the Roosevelt-Hull response to the Catholics was to demand that any peace plan had to start with the Japanese removing their troops from both China and Manchukuo. They knew the Japanese would never agree to that.
In the end things worked out well for the Americans, but not for the Catholics or Japanese. Hitler was supposed to have conquered the U.S.S.R. by December 1941, but instead ran into walls of steel in front of Moscow and Stalingrad. The Japanese won the Battle of Pearl Harbor (Hull says the U.S. ambassador to China warned him of the attack plan almost a year in advance: see page 984) even as a large U.S. invasion fleet was steaming across the Pacific towards the Philippines.
America got dominance of Asia. Hull and Roosevelt claimed the U.S. was helping Asian nations against Japanese imperialism, but after winning the war the Asian nations were returned to their European imperialist masters.
In retrospect, no one looks good. Every major player was motivated by greed and willing to use massive violence to achieve their ends. Everyone committed war crimes and crimes against humanity.
The Pope should have been tried for war crimes and crimes against humanity, but became increasingly pro-American as Hitler and Mussolini's armies were defeated. Basically, Roman Catholic voters in the U.S. saved his hide, and he was allowed to take up anti-atheism, anti-Communism under the new guise of free-market liberal Catholicism and the Cold War.