Though there is only a passing mention of the USSR in Fallout 3, would it be safe to assume that the Soviet Union would have generally existed in a state of detente with the US? If that is the case, then I would assume that the Soviet Union would have been very profoundly effected by Khrushchev and De-Stalinization. So therefore would it be safe to assume that the USSR of the Fallout Universe would resemble that of Gorbachev's Reforms of Glasnost and Perestroika?

Or it could have been still as repressive as in Stalin's times, but the US allied itself with the USSR because both were threatened by China, just like they allied against Hitler during WW2.