(1941) The United States would not enter the war until after the Japanese attack on Pearl Harbor in December 1941. But by the spring of 1941 Congress had approved the Lend Lease program, and the aid Roosevelt had promised at Charlottesville had begun to flow to Great Britain, where Winston Churchill was now prime minister. In July 1941, Roosevelt and Churchill met for the first time in Argentia Bay off Newfoundland, to issue a joint declaration on the purposes of the war against fascism. Just as Wilson's Fourteen Points delineated the first war, so the Atlantic Charter provided the criteria for the second.
Originally the Soviet Union, which had been attacked by Germany the month before, was to sign the charter as well. But the notion of "one world," in which nations abandoned their traditional beliefs in and reliance upon military alliances and spheres of influence, did not appeal to Joseph Stalin, and, in fact, neither was Churchill particularly thrilled. Only Roosevelt, who had been a member of the Wilson administration, truly believed in the possibility of a world governed by democratic processes, with an international organization serving as an arbiter of disputes and protector of the peace.
For further reading: James McGregor Burns, Roosevelt: The Soldier of Freedom (1970); Gaddis Smith, American Diplomacy During the Second World War (1964); and Robert Divine, Roosevelt and World War II (1969).
Stalin Intended as Signer?
First off, the term "Atlantic Charter" wasn't even coined until about August 19, 1941 by the London Daily Herald, a socialist newspaper. The "Joint Statement" issued by FDR and Churchill on August 14, 1941, was never a signed document, nor was it ever meant to be a signed document. It was a press release of supposed ideals. It is pure conjecture to say that Joseph Stalin was intended to be a signer "also" since there were no signers. No one signed the Atlantic Charter. If you doubt this, consider that at a press conference on December 19, 1944, FDR was pressed by the question, "Did Churchill sign the Atlantic Charter?" FDR replied, "Nobody ever signed the Atlantic Charter." Transcripts of this press conference still exist.
Copies of the original coded telegrams showing that FDR directed Stephen Early to use the term "signed" and then naming himself and Churchill are in the archives. FDR is the one who said the statement was signed. It was not then, nor ever has been.
The Atlantic Conference at Argentia was about much more than agreeing upon the wording of a statement of ideals. It was a war council concerning logistics, secret of course, and quite illegal since the U.S. was still technically neutral.