What was Mussolini's contribution to the outbreak of World War II?

Benito Mussolini did not play a major part in the outbreak of WWII.  In fact, Hitler started the war without consulting Mussolini.  He gave Mussolini only one week’s notice that the war was going to start, clearly treating him as something less than an equal.  Mussolini’s main role was as someone who helped pave the way for Hitler to rise to power and to believe that he could take on the French and the British.

Mussolini’s first role was help get Hitler into power.  Mussolini came to power in Italy more than a decade before Hitler took power in Germany.  His rise to power helped to inspire Hitler, and Hitler’s fascist thinking was influenced by Mussolini’s.  The existence of a fascist state in Italy helped convince Hitler and the Nazis that they could also take power in Germany someday.

Mussolini’s second main role came in foreign policy.  Mussolini helped the fascist side in the Spanish Civil War.  He also invaded Ethiopia, defying the League of Nations in his attempt to build an Italian empire.  Both of these actions emboldened Hitler.  The fascist victory in Spain, which Germany also aided, helped convince Hitler that he could defeat the French and British militarily.  Mussolini’s conquest of Ethiopia showed Hitler that the League of Nations was weak and would probably not do anything to stop him from trying to take power over more of Europe.

These are the main ways in which Mussolini contributed to the outbreak of WWII.  Hitler was truly the driving force behind the war.  All that Mussolini did was to enable Hitler, making it more likely that the Nazi leader would cause the war to begin.