<P> Although it has been debated whether the Soviet Union intended to invade Germany once it was strong enough, Germany itself broke the treaty and invaded the Soviet Union on 22 June 1941, starting what was known in the USSR as the "Great Patriotic War". The Red Army stopped the seemingly invincible German Army at the Battle of Moscow, aided by an unusually harsh winter . The Battle of Stalingrad, which lasted from late 1942 to early 1943, dealt a severe blow to the Germans from which they never fully recovered and became a turning point in the war . After Stalingrad, Soviet forces drove through Eastern Europe to Berlin before Germany surrendered in 1945 . The German Army suffered 80% of its military deaths in the Eastern Front . </P> <P> The same year, the USSR, in fulfillment of its agreement with the Allies at the Yalta Conference, denounced the Soviet--Japanese Neutrality Pact in April 1945 and invaded Manchukuo and other Japan - controlled territories on 9 August 1945 . This conflict ended with a decisive Soviet victory, contributing to the unconditional surrender of Japan and the end of World War II . </P> <P> The Soviet Union suffered greatly in the war, losing around 27 million people . Approximately 2.8 million Soviet POWs died of starvation, mistreatment, or executions in just eight months of 1941--42 . During the war, the Soviet Union together with the United States, the United Kingdom and China were considered as the Big Four of Allied powers in World War II and later became the Four Policemen which was the foundation of the United Nations Security Council . It emerged as a superpower in the post-war period . Once denied diplomatic recognition by the Western world, the Soviet Union had official relations with practically every nation by the late 1940s . A member of the United Nations at its foundation in 1945, the Soviet Union became one of the five permanent members of the United Nations Security Council, which gave it the right to veto any of its resolutions . </P> <P> The Soviet Union maintained its status as one of the world's two superpowers for four decades through its hegemony in Eastern Europe, military strength, economic strength, aid to developing countries, and scientific research, especially in space technology and weaponry . </P>

The us and the soviet union became important members in