What if Operation Uranus, or rather the simultaneous push to encircle and destroy the Sixth Armee (though the entirety of Armee Group B was also a target) in the winter of 1942, was an unmitigated disaster to point where most, if not all Red Army combatants are captured and killed with the Sixth Armee still alive.
Could Stalin as a political figure survive the aftermath?
With their position in the south still somewhat secure, could the German push on in the Spring of 1943?
How does this effect LL and DDay planning?