It is a mystery, and a lot of secret history may hinge on it.
I came across it last night while reading The Memoirs of Cordell Hull. Or rather, I did not come across it, because it is a lacuna, or gap in the record.
Cordell Hull was one of the most important figures in American history, though he is now largely forgotten. The highest office he obtained was Secretary of State, under Franklin Delano Roosevelt (FDR). But why was he appointed to that high office? He is the man who brought us the income tax, back when he was a Democratic representative from Tennessee. You would think at least the Tea Party would want to know about the guy. He also brought us Free Trade, or at least a major step in that direction. As Secretary of State he was largely responsible for an unnecessary war with Japan, while evading as long as possible doing anything about Adolf Hitler.
I am reading his Memoirs as my last major research task before drafting my U.S. War Against Asia. His Memoirs are vast: two volumes, 1800 pages of fine print. Only one printing was made [MacMillan, New York, 1948], with most copies doubtless bought by libraries. So far I am only to page 718, in the opening days of what later would be called World War II.
I mention the size of the book because it emphasizes the gap. Hull loved to document and explain his actions in glorious detail.
On page 713 Hull begins recounts his initiative to get Pope Pius XII involved in a peace process, starting in July 1939, well before Germany invaded Poland (regaining the territory lost in the peace settlement after World War I). This account goes on to page 716, corresponding to March 1941. While interesting of itself for the light it throws on U.S. and Vatican war aims, it flashed in my mind that I thought Vatican Secretary of State Eugene Pacelli, before he became Pope Pius XII, had relations with the FDR regime .
I pulled out my copy of Hitler's Pope: The Secret History of Pius XII by John Cornwell, and sure enough, Cardinal Pacelli had visited the United States from October 1936 until November [see pages 176-178]. He met with FDR on November 6, just after FDR had won a second term. They had made a deal, possibly set up and executed by Francis Spellman, then a bishop but later known as Cardinal Spellman. The Roman Catholic Church silenced Father Charles Coughlin, an influential radio-based critic of FDR. Pacelli, in return, received a promise that FDR would work to restore direct relations between the U.S. Government and the Vatican, which had made a treaty with Mussolini in 1929 (see Lateran Treaty) to become a sovereign state as well as the center of a global religion business.
The context for this is important and mostly forgotten. There were two core constituencies of the Democratic Party. There was the southern, racist, white, mostly conservative and Protestant southern wing. In the northern and western states, normally majoirty Republican, the Democratic Party was mainly urban, working class, and Roman Catholic. Holding that coalition together from the Civil War until the 1970s was a great political feat. FDR needed the Roman Catholic Church to stay in power. But the southern democrats did not like that very Church. At the same time, the Depression and popularity of the New Deal (or at least the blaming of Herbert Hoover) brought many former Republicans into the Democratic Party.
So why the lacuna? The Vatican Secretary of State visits America, makes some deals, even has a documented meeting with President Roosevelt. Cordell Hull, Secretary of State, who in his own words ran most American foreign policy with only moderate direction from the President, has nothing to say about it?
You can call it speculation, but I call it analysis. Pacelli had been working on a long-term plan for Roman Catholic domination of the globe, starting with Europe. Mussolini was cooperating in Italy, but Adolf Hitler, a Catholic, had been chosen by Pacelli to lead God's work, which included converting or exterminating atheists, socialists, communists, and even democrats, republicans, protestants, and of course Muslims, Jews, and other religious sects. Roosevelt had a different agenda: American imperialism, on the model of the British Empire, with democracy in the home company serving as a cover for a global dictatorship. Both Roosevelt and the Pope (as well as Hitler and Stalin) knew the biggest global prize was the British Empire. The Popes wanted it brought back under their religious sovereignty, but that would be second step, after Hitler defeated Russia. FDR wanted it to collapse just enough to allow the U.S. to take it over.
The Popes hoped important men in the U.S., even if not religious themselves, would eventually make the U.S. a Catholics-only nation. In the meantime, they did not want the U.S. economy used to build up the armies of anti-fascist governments and groups in Europe. In 1936 the issue was Spain, where the Pope's pet General (Francisco) Franco had launched a civil war, murdering everyone who disagreed with him, including Roman Catholics who supported the democratically elected government. Probably Pacelli and FDR agreed the U.S. would not arm the elected Republican government of Spain, thus ensuring Franco's eventual victory.
What Pacelli wanted long term was for Hitler, when his armies were ready, to have the freedom to attack Russia (aka the USSR) and destroy Communism and Atheism with one blow. But it's a complex world. While Hitler did eventually attack Russia, and engulfed that region in an Atheist Holocaust, the Pope and Cardinal Spellman were not able to convert Roosevelt to Catholicism. With the defeat of the fascists Catholicism suffered a major setback. The Popes had to spend 30 years trying to convince people that they had never even liked Hitler, Petain, Mussolini and Franco. America did inherit the British empire, got the French empire thrown in as well, occupied Japan, and would have gotten China for good measure if it had not been for the Chinese Communist Party.
The negotiations with Pacelli in 1936 probably continued after he became Pope Pius XII; certainly Spellman retained the ear of both FDR and the pope. The peace negotiations of 1940 went nowhere because there were several very different versions of peace involved. Hitler wanted peace if he could keep Poland and prepare for further advances to the east, in line with the papal plan. Britain and France wanted peace if they got to keep their empires and Germany had to give Poland back. America wanted peace because it was good politics, but we know FDR was hoping the European powers would do a World War I repeat: draining each other so that the United States of America would become the new global imperialist power.