Assuming that France and the UK declare war on the USSR following the soviet invasion of Poland in 1939, what are the later implications on Hitlers plan to eventually invade Russia?
My thoughts are that iwere the USSR and Germany to be come co-belligerents in this way, it would be unlikely for Hitler to want a significant Soviet contribution for the Western campaigns, and also unlikely for Stalin to send such aid if it was asked for.
At most I could see a token force of a division being sent to the invasion of France, and perhaps a few fighter squadrons during the battle of Britain. I believe the main Soviet contribution would a large invasion of Iran and Iraq in late '39 or early '40.
If this did occur and come mid '41 a large soviet army group was fighting the British in the middle east and western India, would Hitler still backstab Stalin and launch Barbarossa?
What would happen if he did?
How far could the soviets have gotten in the region by that point?