1. strategic mistakes and major mistakes in military command. Second, the national strength is weak. Compared with the Soviet Union, Germany's comprehensive national strength, especially its land area and total population, is too large, not to mention the resource gap. Third, the international environment is unfavorable. Germany's attack on the Soviet Union eased the pressure on Britain. In addition, the United States entered the war, Germany fought on two fronts, and its allies were not strong enough. Fourth, the opposition in Germany has gradually shaken the hearts of the people. Justice and injustice will win or lose in the end.