Balkanization is very likely under a collapse scenario as the states try to prop themselves up against one another. The moment they are no longer tied together economically, e.g. through imperial unequal exchange via militarism, they will be (1) impoverished and facing domestic unrest and (2) seek to maintain and expand their power, basically becoming (nearly failed) independent states. Who can say what boundaries would exist, it would depend on both larger economic trends and our ability to organize. For example, if the feds are weak/abandoned when the US has a dispersed and self-sustaining industrial base that is very different from a scenario in which it has concentrated agriculture and is reliant on imports. A reliance on imports would mean that border states control import but are dependent on wherever agriculture is viable. Any state with neither is immediately vulnerable, paying economic rent to both kinds of states. Under a dramatic collapse those areas would experience exodus and only become a target of acquisition by powerful interests for natural resources. At the same time, it is possible that by that time the surrounding states had locked down their borders.

The exact circumstances are difficult to predict because they depend on developments beyond our view. But we can predict the kinds of things that might happen and why. We can also say that Balkanization requires precedents, that it is quantitative change becoming qualitative, and that the major binding factor is US impeeialism and that without it the states would likely turn on one another.