I don't understand the logic in this tweet. Why would a break up of USSR/Russia be a bad thing for the US? If anything, I see it as a benefit: instead of a unified Russia fighting the US, it would be a fragmented, weakened Russia fighting itself. Just look at middleast today.. compared to a unified middleast (i.e. under the Ottomans) that terrified the Europeans for centuries.
Many reasons. In no particular order:
Better the Devil you know.
The USSR was a known and defeated quantity. The US objective would have been to essentially lock everything about it in place so it never changed and as such, is forever contained and neutralised.
For a country to fragment would by definition it would result in an effective revolution in all resulting new states created. That can lead to a whole new paradigm emerging after the havoc that is far more competitive against the west. As has happened with modern Russia.
Nuclear proliferation
Russian nukes are scattered all over its territory. A break up of Russia will immediately multiple the number of nuclear powers on the world stage. While the west was able to roll back nuclear proliferation following the fall of the USSR, no way that will happen twice with Libya and Ukraine as cautionary tales.
Increased risk of conflict and war between the newly created states
Once the dust has settled and a powerful, overwhelmingly powerful country emerges from the newly created independent states, there would be a great temptation for it to reabsorb the other new countries to restore the old Russia. That would put the US in an impossible position. Intervene and potentially get dragged into a nuclear war. Or let Russia reform, rejuvenated and more powerful than ever.
Potential unfavourable combinations
Alternatively, if Russian fragmented, it’s possible for chunks of it to willingly be absorbed by China, making China significantly more powerful, self sufficient and potentially at America’s literal doorstep.
Then there’s all the economic and human and social impact of it, such as economic recessions world wide from the disruption to supply chains, massive refugee crisis in Europe etc.
The overriding American obsession is control and subjugation. It’s easier to subvert, sabotage and control one country than many.