The US military is the most powerful in the world, which gives it a hegemonic position. However, US is the world's largest debtor nation. This won't matter much (despite what the politicians say) if the debts aren't called in. A surprising array of countries could call in their Treasury Bonds, including a number of Less Developed Countries such as the Philippines, Brazil and Mexico. Third largest US Bond holder is a conglomeration of 'oil exporters' ( Oil exporters include Ecuador, Venezuela, Indonesia, Bahrain, Iran, Iraq, Kuwait, Oman, Qatar,Saudi Arabia, the United Arab Emirates, Algeria, Gabon, Libya, and Nigeria.)
See this list:
Adrienne Reid (student, INTL 5400, Summer 2011) wondered why Greece's national sovereignty is at risk due to its debt, but not the US'. She writes that Greece has no competitive advantage. But the US has: its vast military expenditure, financed by taxpayers. She writes:
'The other major difference that distinguishes the U.S. from Greece, is that US debt is denominated by its own currency, over which it has sovereign control...The government holds within its ability to create money at will, to cover debt...When Greece replaced it national currency with the euro, the basis of its economic sovereignty was forfeited.'
I suppose the Federal Reserve, which is not a government institution, could deny the US government a request to print money. And, possibly, the US could one day face a fire sale.
In June 2011, Greece put €50bn of national assets on sale in hotel ballroom but private equity firms were not interested. But China, Japan etc will be very interested in any nationally owned US real estate up for sale. US national sovereignty will be also impaired by massive budget cutbacks curtailing military spending.
Feminist International Relations theorists sum up the changing balance of power of states, as a non issue. The King is dead, long live the King. In other words, a new type of hegemony composed of mainly male elites, will emerge. How enlightened it will be, remains to be seen.