Here's a challenge:
POD sometime between late 1970s and mid 1980s that leads to the collapse of the USA in the late 80s or early to mid 90s. Collapse defined as breaking up of states and territories of the USA somewhat similar to what happened to the USSR in OTL. Simultaneously, the USSR survives to the present and is "reinvigorated" by the collapse of its primary foe. There is no direct conflict between the US and the USSR. The POD would have to be a good one that simultaneously leads the US to its demise and helps the USSR avoid its own.
Possible impacts and other issues:
Would there be civil war in/ between any of the states? Any other kinds of internal conflict? International intervention? What would be the fate of the US military (especially forces stationed abroad and the nuclear arsenal)? Would there be any states that attempt to remain united as the USA? What would be the role and fate of the US two party system in such a collapse? What would happen to the american and world economies? What would happen to american consumerism, pop culture, and social values? What might happen to international environmental and human rights efforts in a world with the USSR as the only, or atleast primary, super power? What other issues would be relevant in the causes and outcomes of such a reverse end to the coldwar?
Bonuses:
Bonus for not having the USSR "go Chinese;" by which i mean it doesn't invite in capitalism, but remains a command economy. It might stay authoritarian or become even more authoritarian. Alternatively, Gorbachev or some other reformer might send it down a more progressive path, albeit still a communist one.
More bonus, if the USSR can somehow extend its influence in the 90s and 00s into the PRC and/ or western europe and/ or japan and/or north america.
Triple bonus if afghanistan, iran, iraq, and syria are all somehow cemented into the soviet sphere. same goes for central america and other parts of the third world. wether desert storm happens or not is up to you.
quadruple mega bonus if the US collapse spills over into canada and/ or mexico and/ or western europe, japan, australia, etc
its a challenge, but my gut says something like this may've been possible. feel free to shoot this down as impossible or ASB though, because it may very well be. interested to hear responses.