There is no telling where the widening split between America and its allies will lead all of us, the US included. There would be no “global system” or any kind of formal arrangement in place to govern the interactions of the principal players. Of course, the problem with the Concert of Powers scenario is that it is predicated on a formal, clearly negotiated settlement of all outstanding issues – i.e. A world running on imperial logic has little place for nationalism or even “statehood”, while sovereignty and legitimacy can hardly stand by appeal to the law or the constitution. The scenarios presented here are merely possibilities and perhaps templates, not forecasts; the future is all to play for.