when notified that the German invasion has started and the Red Army was in full retreat and the Red Airforce destroyed on the ground, Stalin is said to have had a "nervous collapse" when told of the invasion and did not speak for 11 days.
the Americans immediately had to rush aid, arms & supplies to the Soviets to counter the German army and open a 2nd front in Normandy to take the pressure off the Eastern front, else Hitler would have wiped out the Soviet communists.
