The latest the USSR could have plausibly been saved was 1985, if Romanov or Grishin won out over Gorbachev. Assuming that, we still see the Soviets introducing limited economic reforms but without glasnost. The Cold War enters a less active phase in the 1990s. The Reagan era is still seen as a success and the Gulf War still happens. Foreign policy is a little more of a concern but that's about it. Maybe enough to swing the very closest state to Bush.
President George Bush (R-TX) / Vice President Dan Quayle (R-IN)
Governor Bill Clinton (D-AR) / Senator Al Gore (D-TN) ✓
Businessman Ross Perot (I-TX) / Admiral James Stockdale (I-IL)