The S.U. had advantages, and some serious disadvantages. Not yet mentioned:
1: Operate carriers and battle fleets into Murmansk and Arkhangelsk, rendering the Kara peninsula including Leningrad vulnerable to attack.
2: If a landing force takes Murmansk, the Finns can be supplied directly from the North.
3: Since we have Denmark, the Baltic is our pond. Liberation Movements in Estonia, Latvia, and Lithuania can be supported. Finland can be supported directly.
4: If a landing force takes Arkhangelsk, Moscow is 600 miles South. This would divert divisions from the Western Front to secure the Northern Front. The threat of doing this would divert forces.
5: The Finns have no love of the Soviet Union, and Allied air groups operating from Finland could hit most of Soviet industry.
1: Stalin knew all these things. He held on to half of Europe because we (U.S. Gov't) were sympathetic to the Bigger-Nazis-Than-German-Nazis. Plus, Hitler had done more to unify the disparate peoples of the S.U. than Stalin had.
2: Stalin did not care for the blood of his people, so long as he won all was good. So the S.U. appeared ready to 'go the second mile'.
3: Another question is Morale: How much fight did the Americans have in them at this time? The Nazis were the objective and it was obtained; continuing to Moscow "wasn't signed up for". Since England and France hadn't vilified the Soviets for Poland's sake, the false message of Stalin being our ally stuck. Stalin "the Father of Nations" (his words) has no allies, only subjects, enemies, and useful idiots. England and Germany were rather exhausted, France cared only for France, and the loyalties of the peoples and governments of South Europe are not well known to me.
Cheap Philosophy: Don't start a war unless you can't afford not to win. Don't start a war you can't afford to lose.
Perhaps this train of thought shaped decisions at the time.
I appreciate your reply. A couple thoughts:
1. The shipping routes to Murmansk/Arkhangeslk were notorious during the war for the impact weather had on the ability to keep supplies flowing. Supporting a large amphibious force, creating a beachhead, and then maintaining that beachhead would be no small feat.
4. Agree that a flanking attack would divert Soviet forces, but the landscape between Murmansk and Moscow is also very difficult for military maneuvering. Lots of swampy terrain and uninterrupted forest. A landing and then drive to Moscow from the north seems impractical. Additionally, weather would impact the western allies who had less experience maintaining functional operations than the Soviets. Seems like a lot of effort for minimal gains. If a second front is required it seems that there would be other locations that could be established sooner and on more favorable terms.
3. Agree, however, I am less inclined to believe that naval operations could be conducted at will until full control of the air. The entirety of the Baltic would be reachable by the VVS until air supremacy was achieved.
A. One thing that I believe you are overlooking is the longstanding enmity between the U.S. and the USSR that predates the war. Until Germany's invasion of Poland, Stalin and the USSR were seen as the real threat to America. Whats telling about American opposition to the Soviets is how quickly they turned on their former ally immediately after the war.
B. If I recall correctly, the motivations for the USSR holding on to Eastern Europe were more complex. First, the USSR was determined to establish an expanded boundary to prevent another invasion. While the USSR had emerged victorious in the second war, it was disastrous overall for the country. Given that this was the second such calamity in thirty years moving the border west several hundred miles was as an existential action. Second, the USSR was committed to the concept of Germany "never again" rising up and threatening the people of the Soviet Union. One of the most telling experiences of this mindset was how Berlin was treated by the Soviets in the post war. Until the wall fell and reunification, the heart of Berlin, the museums and government buildings were left pretty much as they were on May 8th. As a reminder to the German people of what had been.
C. The allies (UK/USSR/US) established a demarcation line for their forces to stop. All sides adhered to this agreement and there was no additional land grabbing. The Soviets were given the "honor" of capturing Berlin even though American forces had a reasonable chance of taking it first. American leadership rightly felt that while German forces seemed to be largely letting American forces advance there would be more fanatical resistance in Berlin. American leadership was also concerned about overextending their supply lines and a further east advance would hinder the Army's ability to fight. The agreement between the Soviet Union included a commitment from the USSR to join the conflict against Japan which they did.