There were numerous historical precedents for the unannounced military action by Japan , but the lack of any formal warning Warning , particularly while peace negotiations Communication were still apparently ongoing , led Causation President Franklin D. Roosevelt to proclaim Statement December 7 , 1941 , `` a date which will live in infamy '' .

And I hereby proclaim Statement and declare Expressing_publicly that if any person , under the pretended authority of the said States , or under any other pretense , shall molest a vessel of the United States , or the persons or cargo on board of her , such person will be held Defending amenable to the laws of the United States for the prevention and punishment of piracy .