Eh? What corner would that be?
The Japanese were an expansionist nation prior to WWII. They had invaded China in the 1930s and had taken over and militarized many of the Pacific Islands, including the Philippines, and then bombed our Pacific fleet at Pearl Harbor. What corner were they backed into to cause that?
FDR's sanctions deprived Japan of the resources it needed to wage an offensive war. That gave the Japanese two options: 1. Stop its expansionism, or 2. Seize the resources it needed to wage an offensive war, by expanding its offensive war. I don't think FDR bears any responsibility because the Japanese chose to expand their war. I think that FDR, and his civilian and military advisers, bear a lot of responsibility for not adequately preparing for what would happen if the Japanese chose option 2.