The surprise attack of the Japanese on Pearl Harbor, followed by the precipitate declaration of war on the United States by Germany and Italy, brought to an abrupt end a prolonged period of uncertainty and indecision in American public sentiment and foreign policy. The fall of France, more than a year before, and the subsequent threat of a Nazi invasion of England had, to be sure, convinced a majority of Americans of their great stake in the survival of Britain. That conviction had been expressed in the widespread approval of the famous Destroyer-for-Bases Deal of September, 1940, despite the fact that the transaction was tantamount to the abandonment of American neutrality. During the ensuing months it was reaffirmed by popular support for the policy of all aid to the embattled British, short of war. As embodied in the Lend-Lease Act, this policy clearly involved active American participation in the European conflict on Britain's behalf.
Yet most Americans still cherished the fervent hope that unstinting provision of military and other aid to the opponents of Hitlerism might spare their country involvement in actual hostilities. They clung to this hope for another full year, despite the fact that militarily the democratic cause fell on ever more evil days. France and Spain, so it seemed, would soon succumb to Nazi pressure and open the way to Axis conquest of Gibraltar, which in turn might well prove the prelude to Axis control of North and West Africa and possibly to a Nazi assault upon the bulge of Brazil.
Though Britain withstood the ferocious air attacks of 1940, Hitler elsewhere scored one signal triumph after another. In the eastern Mediterranean the situation was particularly threatening in the spring of 1941. General Wavell's initial victory over Graziani's Fascist forces in Libya was soon undone by Rommel's spectacular advance on Egypt. This coincided with the dramatic Nazi Blitzkrieg which engulfed the Balkans and came to a halt only on Crete and at the portals of European Turkey. Even when, in June, 1941, the Fuehrer overreached himself in the effort to liquidate his erstwhile Soviet ally, neither London nor Washington felt that much consolation was to be derived from this astounding reversal of Nazi policy. Hitler's victory over Stalin seemed a foregone conclusion and there was every reason to suppose that the Nazis, once they had secured their rear, would again throw the full weight of their military power against the west.