Read this passage FDR's speech to congress after the attack on Pearl Harbor:
Indeed, One hour after Japanese air squadrons had commenced bombing in the American island of Oahu, the Japanese ambassador to the United states and his colleague delivered to our Secretary of state a Formal reply to a recent American message. And while this stated that it seemed useless to continue the existing diplomatic negotiations, it contained no threat or hint of war or of armed attack.
Which Idea from this passage is implicit?