anzus american century asian century asymmetric warfare bric bait and bleed balance of power in international relations balancing blackmail british empire buck passing chinese century covert operation energy superpower geopolitics german language great power hard power historical powers hyperpower international community international relations martin wright middle power military military power projection nato next eleven nuclear warfare polarity in international relations political power potential superpowers power in international relations power transition theory realpolitik regional power second superpower shanghai cooperation organisation soft balancing soft power sovereignty superpower superpower collapse superpower disengagement tariff world war ii