Summary: Some of the great questions that arises from WWII is: Did FDR know in advance about Pearl Harbor? Was the Japanese attack unprovoked? FDR knew that he could not lead a divided nation into war, that the only was the United Stats could enter the war to aid Britain was to be attacked. To the end, the President created an "incident" in the Atlantic over German U-boat attack on the American destroyer, the USS Greer. It pursued the U-boat, reporting its position to the British. Meanwhile, after Japan's invasion of the Dutch Indies, Roosevelt cut off the American oil supply and imposed a total embargo. On November 5, 1941 General Tojo sent two peace options to the United States with the ultimatum that if neither alternative was accepted Japan would declare war. The United States rejected both proposals. One morning later, on December 7, 1941, Japan bombed Pearl Harbor.