Final answer:
In President Truman's first speech to Congress, his message to Germany and Japan was to demand their unconditional surrender.
Step-by-step explanation:
In his first speech to Congress, President Truman's message to Germany and Japan was to demand their unconditional surrender.
Truman believed that by demanding an unconditional surrender, it would prevent any other nations from engaging in negotiations that would undermine the plans for the defeated belligerents.
It would also serve as a reassurance to the Soviet Union and prepare the Axis nations for a complete postwar transformation.