Italian declaration of war on the United States
On December 11, 1941, Italy declared war on the United States. The declaration followed the Japanese attack on Pearl Harbor four days earlier, and came the same day as Germany's declaration of war against the United States. Benito Mussolini publicly made the announcement in Rome on December 11. Shortly before Mussolini's speech, Italian Foreign Minister Galeazzo Ciano delivered the news to the head U.S. diplomat in Italy, George Wadsworth II.
The Italian, German, and Japanese governments had all signed the Tripartite Pact in 1940, formally allying the three powers with one another. Italy and Germany also signed the Pact of Steel military alliance in 1939. Italy had declared war on the United Kingdom and France on June 10, 1940, as Mussolini implemented the Pact of Steel and leveraged the German alliance to win advantages for Italy. Prior to Hitler's declaration of war against America there was little, if any, doubt that Italy would once again "follow Germany's lead."
The United States Congress immediately responded by declaring war on Italy and Germany, bringing the United States into the European theater of the Second World War. The Axis powers also signed the "No Separate Peace Agreement" on December 11, pledging Italy, Germany, and Japan to not independently make peace with Britain or America. Mussolini is said to have "expressed no reservations" about war with America, blaming the conflict on President Franklin D. Roosevelt.
Background
On December 7, 1941, 353 aircraft of the Empire of Japan attacked the U.S. naval base at Pearl Harbor, inflicting mass destruction on American life and property, and drawing the United States into the Second World War. On December 8, the United States declared war on Japan in response to the attack.Three days later, at 2:45 PM on December 11, 1941, Italian dictator Benito Mussolini announced—from the balcony overlooking the Piazza Venezia in Rome—that Italy and Germany would "participate from today on the side of heroic Japan" against the United States. Adolf Hitler made his war announcement at the Reichstag in Berlin that same day, stating that while he had tried to avoid direct conflict with the U.S., Germany was obliged to join with Italy to defend Japan under the Tripartite Pact of 1940. Hitler also stated, "After victory has been achieved, Germany, Italy, and Japan will continue in closest co-operation with a view to establishing a new and just order."
A memo that U.S. chargé d'affaires to Italy George Wadsworth II sent to the U.S. Secretary of State on December 9, 1941 confirmed that if Germany declared war, Italy would do likewise, stating: "Opinion in well-informed Rome circles is divided on the crying question of the day whether Germany will declare war on the United States. Italy, it is assumed without question, will follow Germany’s lead whatever it be as a matter of course."
At 2:30 PM on December 11, just before Mussolini's speech, Italian Foreign Minister Galeazzo Ciano called for chargé d'affaires Wadsworth and revealed that Italy was at war with America, to which Wadsworth responded: "It is very tragic." Ciano recorded his thoughts on the occasion, saying, “It was three o’clock in the afternoon, the people were hungry, and the day was quite cold. These are all elements that do not make for enthusiasm.”
On December 11, the Axis powers also signed the "No Separate Peace Agreement," pledging each nation to not independently make peace with Britain or America, a decision that theoretically bound Italy, Germany, and Japan to a common fate. Mussolini "expressed no reservations about war with America," and laid responsibility for the conflict at the feet of President Roosevelt.