External pressure seems to produce internal unity. - Kenneth Waltz

I am not saying that such a theory cannot be constructed, but only that I cannot see how to do it in any way that might be useful. The decisive point, anyway, is that a macrotheory of international politics would lack the practical implications of macroeconomic theory. National governments can manipulate system-wide economic variables. No agencies with comparable capabilities exist internationally. Who would act on the possibilities of adjustment that a macrotheory of international politics might reveal?

With many sovereign states, with no system of law enforceable among them, with each state judging its grievances and ambitions according to the dictates of its own reason or desire - conflict, sometimes leading to war, is bound to occur.

It is not true that were the Soviet Union to disappear the remaining states could easily live in peace.