In WWII, the German Army was trapped in St. Petersburg because of the Russian street to street fighting. This was the turning point of the Eastern front. Let's say that the Soviets lose the Battle of Stalingrad, eventually surrendering to the Germans. Hitler, while deranged, gets bright and decides to call for a ceasefire, kicking the Russians out of the war and annexing their land. unfortunately for hitler, this was the beginning of the end.
The Western Powers soon overpowered his Germany and soon (as per OTL) had crossed the Rhine. While the East was still in German hands, the Russians, Poles, etc. soon began very damaging guerilla tactics against the Germans, killing hundreds and destroying vital defense lines. This eventually leads to the German abandonment of much of Eastern Europe, especially Ukraine, Belarus, the Baltic States, Greece, and other occupied territories. Legitimate governments are reinstalled in many places, and the German army is pulled back into German. But it is too late, as the Allies have captured Berlin, and have found Hitler's body, dead, apparently committed by suicide. The German army sdurrenders a few days later. Japan follws suit after 2 atomic bombs are dropped on Nagasaki and Hiroshima.
The next several months face intense standoff between the destroyed Soviet Union (which still asserts its control over the newly independent countries) and the main Western power, the United States. The US eventusally decides to hold referdums in all freed territories. As expected, all countries vote no to rejoining the Soviet Union. Thus begins the COld War and the Soviet Union's gradual decline as a world power...
Anyone interested? We get a nice Eastern Europe...I'm thinking expanded Marshal plan at the cost of the US, a destroyed Soviet Union, a weaker Communist China, and eventually, a stronger, much more integrated Europe...