As Minister of Armaments, Speer was responsible for supplying weapons to the army. With Hitler's full agreement, he decided to prioritize tank production, and he was given unrivaled power to ensure success. Hitler was closely involved with the design of the tanks, but kept changing his mind about the specifications. This delayed the program, and Speer was unable to remedy the situation. In consequence, despite tank production having the highest priority, relatively little of the armaments budget was spent on it. This led to a significant German Army failure at the Battle of Prokhorovka, a major turning point on the Eastern Front against the Soviet Red Army.