[grey_whiskers]

I don’t know for sure if I agree that it was the only reason; I have skimmed other sources (but not read or considered in detail enough to know if they are right) that Stalin was preparing to backstab Hitler by invading to the West, when Barbarossa was launched.

[agere_contra]

It's fair to say that Hitler's Germany was eventually going to have a crack at Russia for all that lebensraum. And I agree, the Soviets would have eventually been happy to backstab Germany, if it had been engaged elsewhere.

But without oil from the US and Venezuala, Nazi Germany found itself on a strict timer. Not enough oil to keep his economy going past a certain date.

If Hitler had been able to seize the Western oil fields of the Caucasus and - moreover - had blockaded oil traffic up the Volga (e.g. at Stalingrad) then the Soviet Union would have crumbled. And maybe the 3rd Reich would still be with us.

But Hitler just couldn't do it. He didn't have enough oil to maintain offensive military operations for long enough.

We talk about 'General Winter' defeating the Nazis. But it seems Hitler lost WW2 in the Atlantic. Mainly because he couldn't get a thimbleful of oil across it.