Political instability: All three countries were experiencing political instability in the years leading up to World War II. In Italy, there had been a series of weak coalition governments, while in Germany, the Weimar Republic was struggling to cope with the economic crisis and the rise of the Nazi Party. In Japan, the military was increasingly asserting its influence over civilian government.
Social unrest: All three countries were also experiencing social unrest in the years leading up to World War II. In Italy, there were widespread strikes and riots, while in Germany, the Nazi Party was exploiting social tensions to its advantage. In Japan, there was growing discontent with the government's handling of the economy and the military's increasing power.
Nationalism: All three leaders were nationalists who appealed to the sense of national pride and superiority of their respective peoples. They used this nationalism to rally support for their fascist regimes and to justify their aggressive policies abroad.
Anti-Semitism: All three leaders were also anti-Semitic, and they used this hatred of Jews to scapegoat for their countries' problems. In Germany, the Nazis pursued a policy of systematic genocide against the Jewish people, while in Italy and Japan, there was widespread discrimination against Jews.
These are just some of the factors that Hitler, Mussolini, and Hirohito preyed upon when gaining fascist power before World War II. By exploiting these conditions, they were able to consolidate their power and lead their countries into war.