Mossad was formed on December 13, 1949. Roosevelt dies in April 12, 1945. You do sound like a conspiracy nut.
In any event, Israel, the new nation, was recognized quite swiftly by FDR's successor, Harry the Bomb Dropper with a D after his name.
At midnight on May 14, 1948, the Provisional Government of Israel proclaimed a new State of Israel. On that same date, the United States, in the person of President Truman, recognized the provisional Jewish government as de facto authority of the Jewish state (de jure recognition was extended on January 31, 1949).
The haberdasher was cut from a superior bolt of cloth, as compared to his predecessor.