The United States is certainly at the moment a great power by any definition. We are the only country on earth capable of projecting force anywhere at any time. The U.S. GDP is almost three times that of the next biggest country, Japan and is roughly the equivalent of the next four added up (Japan, China, Germany and France.) To get a different perspective on the size of the U.S. economy relative to that of the world, take a look at this two-year old map comparing the size of the economies of U.S. states to those of other countries.
We have plenty of political juice, are the leading force in the alliance that spends 85 cents of every defense dollar on the planet and helped design the international system in ways that it reinforces our position. We're also protected by two great oceans and our neighbors are fairly easy to get along with. (Mexico is a bit of a concern at the moment but Canada lost its last remaining offensive capability when Wayne Gretzky moved to the United States.)
All that said, the United States may be nearing the peak of its power. With the U.S. public debt around 90 percent of GDP and likely to pass the 100 percent mark in the next year or two, with well over $40 trillion in unfunded retirement health care liabilities that are unlikely to be significantly reduced anytime soon, and with uncertainty about when our addiction to debt will end, we're just going to have less money to spend for everything...including defense. We're also likely to have less of a stomach for spending on the kind of far-flung efforts associated with projecting force. Iraq-fatigue which will soon be joined by AfPak-fatigue will further dampen our appetite for using that big military we have and we may well take a generally more defensive, less-interventive stance than we have seen in the recent past.
So, what about the other "great" powers? Who are they?
Burns says India will be among them and it's hard to argue with the proposition that India is critically important to world affairs (which is why Clinton's outreach and efforts to institutionalize a stronger relationship were so welcome and timely). But in terms of military capability, although India has a big military (the world's third largest in terms of manpower), it has only the ninth largest defense budget in the world and spends only about a 20th of what the United States spends, it has only one aircraft carrier and while it is expanding its capabilities rapidly as perhaps the largest developing world arms acquirer, it is ultimately constrained by the size and state of its economy. While growing rapidly, it still has a nominal per capita GDP of just over $1,000 a year, ranking it 142nd in the world. Roughly 80 percent of the population live on less than $2 a day and according to some estimates the almost 90 percent who live on less than $2.50 a day on purchasing power parity terms represent a larger chunk of the population than who live on the same meager amount in sub-Saharan Africa. The country is heavily dependent on foreign oil imports, half the children are malnourished...it's growing, it's a great story, it's a remarkable achievement in democracy, but it's ability to project force or throw its economic weight around is severely limited. (It's economy is smaller than that of Canada which, as noted earlier, is no one's idea of a great power...even though they're a swell neighbor, a useful ally and could offer great vacation values should global warming continue.)
Ok, then, certainly China is a great power. After all, they have 1.2 billion people. (Although India will soon overtake them as the world's most populous country.) Their economy is growing, according to Morgan Stanley, at a robust 9 percent even in the midst of this nasty "great" recession. They have the world's third largest economy (which is about twice as big as the economy of California) and will soon surpass Japan. They have the world's second largest army and the second largest defense budget...which is about one seventh that of the United States. They are upgrading their capabilities but unlike the United States or other would-be great powers on this list they do have as a significant military consideration maintaining the integrity and stability of their country in the face of restive populations in far-flung regions. Despite China's economic growth it faces the paradox of labor shortages and perhaps as many as 150 million unemployed or under-employed citizens floating unsatisfied through society. It is heavily dependent on foreign imports of food and energy as well as on a faltering U.S. market. Around three-quarters of its reserves in U.S. dollar denominated instruments which shows a heavy dependence on a potential rival (that's a two way street, of course.) And despite astonishing progress in reducing poverty, in terms of per capita income China is still poor, ranked at somewhere between 100 and 110 among all countries worldwide. Finally, China is ill-at-ease on the world stage, uncomfortable throwing around its political weight and still reluctant to intervene far from home except economically (which will lead, of course, over time to growing influence abroad.)
Who else? The EU would be a great power in economic and military terms...if it actually had a workable means of achieving a common foreign policy and the will to actually project force. Its individual members, notably Germany, France and the U.K., are important powers, 4th, 5th, and 6th respectively in GDP...but France is home to only the 17th largest military in the world, Germany the 20th largest and the U.K. the 32d largest. What's more, Germany is particularly reluctant to project force (much to the relief of anyone with a memory), France does so seldom and the U.K. is developing a pretty bad taste in its mouth in that respect recently. Japan is still legally constrained from projecting force and, while it is the world's second largest economy for the moment (say the next three to five years), that status, is fading and its economy is struggling. While it might be expected that in the next few years Japan will normalize it's military, it is still unlikely it will be useable for much beyond defensive and multilateral actions for the foreseeable future. Russia? Lots of nukes -- perhaps 3,000-5,000 warheads putting it alone on a par with the U.S. (the stockpiles of other would be great powers -- the U.K., France, China and India-range from 10 percent of the low end of this total for France to just over 1 percent of the high end of the total for India.) And Russia's economy? Smaller than that of Brazil (and of course, that economic powerhouse, California). It also may contract at as much as 10 percent this year, which is roughly half what some estimate the bad loans in the Russian banking system. But Russia's biggest problem that it is undergoing one of the greatest peace-time demographic collapses in history, with estimates suggesting the population could shrink from almost 150 million to 80 or 100 million by 2050. That would be a population loss equal to or greater than that associated with the Black Plague of the mid-14th Century in Europe.
What's more, many of the great powers are further constrained by participation in global regimes that only grant legitimacy to multilateral undertakings...which are very hard to achieve as we have regularly seen. While Gideon Rachman makes the case for a UN army in today's FT (one with which I agree...there will be no effective NPT 2.0 without enforcement mechanisms that include the ability to wield force to require compliance)...we're a long, long way from there. So the rule of international law has effectively weakened those who did the most to craft it (even if it has, as I believe, improved the general quality of civilization). And who knows what the impact will be of another global economic shock if, as I believe is going to be the case, we fail to fix what is broke this time around? On these big economies? On their ideological underpinnings?
Are these "great" powers nonetheless still greater powers than the others of the world? Certainly. Most of the countries of the world are virtually powerless. Only 25 countries have the ability to field active armed services in excess of 200,000. Of these perhaps 17 would be considered very economically constrained and all but a tiny handful would be useless too far beyond their own borders. Only 25 countries have GDP's larger than the annual sales of the each of the world's 3 largest companies. (Not an apples to apples comparison, I know...but I offer it primarily to underscore the relative smallness of the rest of the world's economies. The 100th largest company in the world in sales, Target, has greater revenue than all but the top 60 or so countries.) Most countries have precious little political influence and that influence tends to be diluted when it is channeled through low-functioning multilateral institutions. It is amplified via effective alliances but precious few of these exist on any global scale.
That said, as striking as the weaknesses of great powers may be, a parallel trend is that which gives the weakest access to powerful technologies (of mass destruction or political persuasion) that enable them to gain previously unavailable global stature and leverage. Twenty five countries are reportedly considering or planning nuclear power programs. Some of these will lead to nuclear weapons programs. Some of these will contribute to proliferation and making new threats available to weak states and non-state actors. And some of those big companies I mentioned earlier are now weighing in, using their global economic clout to influence everything from tax codes to trade regimes to who wins or loses big elections. So the ends are converging on the middle and the terms we are used to, great and small, powerful and weak, are coming to mean something entirely new.