Probably not right away. The F.S.U. gave way to a new state named Russia and a few other independent countries yet interestingly hadn’t much public debt to complicate matters (I believe). The United States has a ton of public debt and if it went out of business it would have the opportunity to eliminate its debt directly without it passing on to a few new nations that emerge from the break-up. With global capitalism being what it is I am skeptical that investors in the debt would allow it.
There are challenging international issue that obviously present a cost to the U.S.A. Foreign wars have often been costly affairs that are harmful to national budgeting (for the British Empire for example in the war against the states). Conflict with China hasn’t much potential in conventional terms; in nuclear and other terms a war would be over quickly and probably destructively for demographics and economics- I think few who realize what that would be want it in China or the U.S.A.
The United States and China (as well as Russia) were more or less on the same side in the last great planetary war and will continue to find ways not to become as adversarial to one another as were the Nazis and Imperial Japan to all three. Since China is allowing a mixed economy and capitalism while Wall Street is heavily investing there as well the greatest battle probably will be in propaganda in the U.S.A. to divide the electorate upon itself so it can never reform economics far toward national ecospheric recovery, elimination of public debt or basic income, free education through graduate school and good public health care inclusively for all citizens.
China may have political leadership problems because of its rising standard of living and great population that drives it to seek to expand over proximal lands and nations that would require containment from the international community, yet it would be ore interesting to try rafting down the upper Yellow river than to watch news about drifting radiation clouds, contaminated areas and starving people, plagues and so forth.
The war in Afghanistan might evolve toward lower costs and military sustainability through various treaties and relationships that allow a continuing U.S. troop presence to defrappe tyranny. Radical Muslims that become terrorists because of hatred for the west have some extreme indoctrination yet also meaningful points in some cases concerning the excesses of decadence that typically emerge in a prosperous culture. There are also great cultural difference between Afghanistan and the U.S.A. that make social progress toward equalization impractical because of the limits of the Afghan economy. Afghan radicals would like the U.S.A. to equalize toward their culture and the U.S.A.- especially Democrats, would like Muslims to move toward their culture. Non-heavy lifting, non-college graduate full employment for females at at a high minimum wage with income equality between genders requires a very prosperous nation to achieve- some Americans don’t understand that and don’t realize the relationship between economics and culture forms well enough to avoid conflict sometimes.
Non-violent gender-based redistribution of income and female independence appear to be long term global trends that are simpler to achieve in corporate and communist bureaucratic economic systems, so I would think that various planetary struggles will flow in part at least stimulated by those policy conflicts. Environmental issues are another source of conflict, and free market disruptions to political ideology that might be regarded as in conflict with market efficiency may complicate the reasons why conflicts are occurring even to those abstractly in support of various conflicts.