While virtually all the historians who have discussed the reasons behind Hitler’s decision to declare war on the US agree that he was resigned to an imminent entry of the US into WW 2, so far no one has made a plausible case for one particular political or military move by Washington tipping him over the edge. From the “Destroyers-for-Bases” deal of September 1940 to the de-facto abolition of the 1939 Neutrality Law an already pro-Allied Roosevelt administration got progressively more and more involved in the war against Nazi Germany while still claiming the status of a neutral. Assessing which of these steps was decisive in predisposing the German leader towards a declaration of war is a major challenge, since no document for internal consumption summarising his thoughts on the matter has ever emerged.

A detailed examination of military and diplomatic records, together with his acolytes’ personal diaries indicates that it was the passing of the legislation which gutted the US Neutrality Law (November 13th) which is most likely to have put him in a frame of mind where war with the US was seen as something inevitable, since this guaranteed the imminent arrival of US civilian shipping in the NW approaches of the UK.