Why did the USSR become frustrated with their allies over Germany?

Answer 1

Josef Stalin, Dictator of the USSR, had demanded that Britain & the United States start a "Second Front" against Germany in Europe to relieve German pressure against Soviet troops, These calls for the "Second Front" began in 1942 after the US was at war. In hindsight, Stalin's position on the issue had severe credibility issues from the start, for the following reasons:

Before Germany invaded the USSR on June 22, 1941, Stalin had conspired against the Allies & economically assisted Hitler in the invasions against Denmark, Norway, Netherlands, Belgium, France & Britain. Stalin's armies had helped Hitler Invade Poland. Stalin had threatened the bordering nations of Finland, 3 Baltic States, Hungary, & Romania to the extent that these nations decided to align themselves with Hitler as a means of protection. In many ways Stalin's policies had helped bring the Nazi threat to his doorstep.

Also before the the USSR was attacked, Stalin gave orders that communists in Nazi occupied countries not resist the Germans. He also directed the communist parties in Allied countries to undermine the Allied war effort against the Nazis. In the United States, the communist party was instructed to push for American neutrality & not assist the British.

Then after the Soviet Union was invaded, the British & Americans mounted large & expensive supply operations to help Stalin's military. The British & Americans mounted aerial bombing campaigns against the Germans from England. Eventually these massive bombing campaigns would tie up large numbers of German fighters & anti-aircraft guns (which are also anti-tank guns) that were prevented from fighting the Soviets. They would do great damage to Germany, cut-off rail networks, oil supplies, and other materials needed by the Germans fighting the Soviets.

The British defense of Egypt, and the November 1942 Invasions of North Africa were in affect the "Second Front" that Stalin wanted. The Allies captured more German & Italian troops at Tunisia in May 1943 then the Soviets had captured at Stalingrad in 1942-43.