The USSR was not the most powerful country in history. The US has certainly been stronger than us, in the economic, political and military terms, both when the Soviet Union existed and now.
Yet, the Soviet Union was closest of all throughout history to what we can call world domination.
Mongols and Alexander the Great were possibly more hell-bent on expansion. But they didn’t have the strategic patience, the ideological platform, and most importantly, the technology to make the entire world their realm.
We had a unique window of opportunity somewhere between the mid-1930s and June 22, 1941. The Soviet Union was militarily stronger than anyone among our neighbors, either in Asia or Europe. At the same time, the rest of the world was too consumed with their own problems and didn’t realize the magnitude of threat that a rising Communist superpower like ours could pose to them. The ascent of Fascism and Nazism made us look like torchbearers for the ideas of progress and humanity, east and west. Communist ideas were at the zenith of their popularity, whether in America or Europe.
Stalin realized that, but missed this window. Hitler hit first and robbed him of the chance to launch a crushing tank attack on Germany somewhere between July ’41 and summer ’42, starting along the entire border in Poland, with an auxiliary operation targeting the oil fields in Ploiesti.
The USSR had an overwhelming military superiority over Wehrmacht in 1941. (Twice or perhaps three times the number of both tanks and aircraft as the Germans, almost 1,000 of them T-34 and over 500 KV tanks.) Within a couple of months the Red Army would have reached the Channel to the north and a few weeks later the Spanish border and Italian Alps to the south. The USSR would be celebrated as the liberator of Europe and saviour of the Great Britain.
WWII would have ended before it really started. The continental Europe, and maybe the rest of the world outside the US-British sphere would have been speaking Russian by now. Seems like George Orwell peeked right through to this alternate reality in his “1984”.
After the A-bomb came, this fork in history disappeared for good.