Germany, Italy and Japan Sign Tripartite Pact
On this day in 1940, the Axis powers are formed as Germany, Italy, and Japan become allies with the signing of the Tripartite Pact in Berlin.
The Pact provided for mutual assistance should any of the signatories suffer attack by any nation not already involved in the war. This formalizing of the alliance was aimed directly at "neutral" America--designed to force the United States to think twice before venturing in on the side of the Allies.
On November 1, 1936, Germany and Italy, reflecting their common interest in destabilizing the European order, announced a Rome-Berlin Axis one week after signing a treaty of friendship. Nearly a month later, on November 25, 1936, Nazi Germany and Imperial Japan signed the so-called Anti-Comintern Pact directed at the Soviet Union. Italy joined the Anti-Comintern Pact on November 6, 1937. On May 22, 1939, Germany and Italy signed the so-called Pact of Steel, formalizing the Axis alliance with military provisions. Finally, on September 27, 1940, Germany, Italy, and Japan signed the Tripartite Pact, which became known as the Axis alliance.
The three nations agreed that for the next ten years they would "stand by and co-operate with one another in... their prime purpose to establish and maintain a new order of things... to promote the mutual prosperity and welfare of the peoples concerned." They recognized each other's spheres of interest and undertook "to assist one another with all political, economic and military means when one of the three contracting powers is attacked" by a country not already involved in the war, excluding the Soviet Union.
The pact supplemented the Anti-Comintern Pact of 1936 and helped overcome the rift that had developed between Japan and Germany following the Molotov-Ribbentrop Pact signed by Germany and the Soviet Union in 1939.
The Tripartite Pact was subsequently joined by Hungary (November 20, 1940), by Romania (November 23, 1940), by Slovakia (November 24, 1940), by Bulgaria (March 1, 1941, prior to the arrival of German troops), by Yugoslavia (March 25, 1941) and by Croatia (June 15, 1941).