They ignored Hitler's advice and on December 7, 1941, the Japanese Air Force attacked Pearl Harbor and declared war on the United States.
Hitler, who had not been told of Japanese plans, was furious at first that the United States had been dragged into the war. Hitler, who had previously called the Japanese "honorary Aryans" claimed that this is what happens what your allies are not Anglo-Saxons.
President Franklin D. Roosevelt declared war on Japan but did not mention Germany in his speech. It was still possible for Hitler to postpone the war with the United States but he decided to honour his treaty obligations with Japan, and on December 11 announced that Germany was at war with the United States. Once again he became a victim of his own prejudice. Hitler claimed that America had been "corrupted by Jewish and African blood" and would be no match for Aryans.
In the second campaign on the Soviet Union Hitler concentrated his attack on Stalingrad. During the winter of 1941-42 the Soviets had reorganised their defences and were able to halt the German advances. In the autumn of 1942 they counter-attacked and by November the German Sixth Army was surrounded. The German Army commander in the Soviet Union, Freidrich Paulus, asked permission to break out, but Hitler, refusing to believe the Soviets could beat Germany in battle, told Paulus to stand and fight. On February 2, 1943, Paulus and the Sixth Army were forced to surrender. Out of the 265,000 men, 100,000 had been killed, 34,000 wounded and 90,000 taken prisoner.
Once again Hitler refused to accept responsibility and failed to learn from the defeat. He blamed Hermann Goering and the Luftwaffe for not providing the Sixth Army with the necessary support. He also claimed that he was travelling by train during an important stage of the battle and was therefore not in a position to direct operations which would have enabled the Sixth Army to defeat the Soviet forces.
The German defeat at Stalingrad was the turning point in the war. The Soviet army now began to advance from the East. For the rest of the war Germany was on the retreat.
Hitler had always found it difficult to cope with defeat. He refused to believe he was guilty of mistakes and instead accused those around him of betrayal. Hitler began to suffer from depression and his insomnia became worse.
Hitler's health deteriorated rapidly. He was constantly ill with stomach pains, headaches, nausea, shivering fits and diarrhoea and was now completely dependent on drugs. In September 1944, Hitler suffered a heart attack and was forced to spend several days in bed.
Hitler was constantly tired. He rarely got out of bed before 11.00 a.m. At noon he was informed of the latest military developments.