After the lawsuit of 18 states joining Texas against some Democratic states (plus 2 counties from California/Nevada which want to become new states), and after that seeing some Texan republicans calling for Texas to leave US and form an union with other states, I wonder what would happen with the external debt of a country if close to half of the states of that country leave it. Do the leaving states retain some responsibility?
There has to be historical evidence about this, but I couldn't find it. I found the USSR split in almost exactly half (USSR population 262 millions, Russia population 137 millions by 1979, I know they split in 1991 but it gives a good idea) and they indeed had an important external debt in 1989 of 55 billion (11th in the world)
So, which country is responsible for the external debt if half of the states of a country become independent?