Patton pushes on (what if)

[Jolt]

Provided that Turkey would allow the USA to rebase their Nuclear Bombers there, while sustaining the advance of the SU, I believe the western SU population centers would be nuked to smithereens (At the very least, Ukraine and the Volga basin) from there that might have had one of two effects. Either the Soviets revolted against the state, leading to quite big revolts since WW1 (Ukraine would probably rise in revolt), or provided the NKVD clamped down on protesters, could lead to a firm rallying under the Soviet banner.

EDIT: Probably, the hittable cities would be Moscow, Stalingrad, Leningrad, Kiev, Odessa, Minsk, Riga, Vilna, Vitebsk, Smolensk, Kursk, and some others. This in the first year provided that they produced a A-Bomb per month.