The Axis Alliance
During the late 1930s and early 1940s, Germany, Japan, Italy, and a few minor nations signed a series of treaties promising military aid, economic connection, and political similarity. If any of these nations went to war or were attacked the other "Axis" Powers were practically obliged to stand by them. Both of these situations were quite likely, because Italy, Germany, and Japan were all interested in world domination. They also agreed politically that Soviet Communism should not be allowed to spread, because they shared authoritarian ideals, highly incompatible with communism.