We sat back and waited for the USSR to win, Parsifal?
Let's see ... the U.S.A. ramped up bombing tonnage every year and dropped more in 1944 on Germany than in all the rest of the war years all combined ... and we were sitting back and waiting for something? You might want to tell that to all the aircrew and ground troops who died in the west. I bet THEY didn't know it and that doesn't even mention naval war.
I'll have to disagree with you here, Parsifal. Not altogether a surprise and it's not an attempt to start an escalting discussion, either. Just a simple, "I don't think so," at least from a U.S. point of view.
The U.S.A is as far removed from the Soviet Front as is possible on a planet of this size ... half a planet away ... an entire ocean AND continent away on both sides, and we had supply lines reaching from the U.S.A. to Europe, the Pacific rim, China, Burma, India, Pacific Islands, Australia and even some to Africa, the North Sea and other points of interest, all simultaneously. Given this and the reality of the state of readiness we "enjoyed" in 1941, I'll have to say we gave it pretty good effort.
The Soviets did what they did and THEN word about it leaked out .. there was no "advance warning of intent to rape eastern Europe and the surrounding area." Yes, we were helping to support the USSR, but were definitely not welcome to fight alongside them on any battlefield, especially in their own territory or any adjacent.
All in all, I'm not too sure what the U.S.A. or the U.K. might have been expected to have done about it as far as prevention goes. We had yet to defeat the Nazis in the West, but were closing in when all this happened. Being accused of waiting is sort of like accidentally walking in on a robbery in progress and then being asked later why you weren't there sooner.
Like most people I decry what happened. But we (the U.S.A., U.K., Canada, and Australia) didn't particpate in the Soviet attrocities, didn't know about them in advance, and most certainly did not condone them. Many years of cold war should at least lend some credence to that assertion.
All that being said, I can certainly see why it might seem that way to the peoples to whom all this happened, who had little to no knowledge at the time of the situation the western Allies were facing. They were VERY occupied with what was happening to them at the time. It might seem as if we abandonded them but, in reality, we had little to no presence there to start with and little in the way of intelligence assets with which to gather information for the most part ... only some small intelligence that came from sympathetic resistance groups with access to radios that could be picked up by us or messages that could be smuggled out by people or public mail.
There were no satellites, no high-flying spy planes with long enough range to look, and little military reason to spy on erstwhile allies in the form of the Soviet Union while we were struggling to win ascendency in the west.
If I am not mistaken, the U.K., U.S.A., Canada, Australia, the Free French, Mexico, and other countries in South America and around the world were fighting on fronts where they could ... but there was never any thought of "invading" the Soviet Union to fight Germany from the north, south, east, and west simultaneously all by ourselves while warring with the Soviet Union at the same time over our "invasion" of their sovreign territory.
We expected the Russians to follow the rules of war as we understood them ... and they didn't. They apparently had limited or no experience with the western concept of "rules of war." I may be wrong, but I think at least the leaders still don't. I doubt we'd expect them to adhere in future conflicts, given their track record in WWII, the cold war, and now beyond the cold war. They might give lip-service to it in a declared war, but very probably not in some regional conflict or semi-local uprising.