On this day in 1940, after withholding formal allegiance to either side in the battle between Germany and the Allies, Benito Mussolini, dictator of Italy, declares war on France and Great Britain.
What caused Il Duce's change of heart? Perhaps the German occupation of Paris did it. "First they were too cowardly to take part. Now they are in a hurry so that they can share in the spoils," reflected Hitler. (However, Mussolini claimed that he wanted in before complete French capitulation only because fascism "did not believe in hitting a man when he is down.")
Italy's lack of raw materials had made Mussolini wary of waging all-out war previously. Britain and France were also wooing him with promises of territorial concessions in Africa in exchange for neutrality. But the thought of its Axis partner single-handedly conquering the Continent was too much for his ego to bear. While Germany had urged Italy's participation in September 1939, at this late date such intervention would probably prove more of a hindrance than a help. For example, despite Italy's declaration of war on the 10th, it wasn't until the 20th that Italian troops were mobilized in France, in the southwest-and easily held at bay by French forces.
The reaction by the Allies to the declaration of war was swift: In London, all Italians who had lived in Britain less than 20 years and who were between the ages of 16 and 70 were immediately interned. In America, President Roosevelt broadcast on radio the promise of support for Britain and France with "the material resources of this nation."