I think extranational organizations-- the UN, World Bank, WTO, International Criminal Court, along with the regional organizations like the EU and OAS (organization of american states), and/or their progeny will eventually make nation superpowers obsolete. The international trend is towards collective security and collective justice, with the rule of law governing international security, justice, and trade. This is why everybody around the world is pissed off at bush for ignoring the UN. His father and Clinton both used the UN for authority for foriegn interventions, allaying any fears of old fashioned imperial designs. In doing so they were continuing a long evolving interntional cooperative spirit that started with the Congress of Vienna. It's an extension of suffrage to the rest of the world, giving small countries a stage and a voice to compete with the holders of military and economic power. Bush's imperial jaunt is seen as a reversion into barbarism. Hopefully international cooperation will strengthen in the face of our arrogance, making "superpower" an obsolete term once it no longer applies to us.