What we may not think about too much is the cold steel underneath the economist's effete calculations. We don't take into account the military planning and contingencies and stockpiling and exercises and most of all - power projection: what happens right after diplomacy fails, sometimes beforehand.
In the colonial era, much of the global reach of the colonial powers was intertwined with their need for military bases - safe places to park fuel for passing warships ("coaling stations"), and eventually contingents of troops and then airfields. Airfields are very powerful.
Almost as soon as airplanes were invented a century ago, people started trying to figure out how to launch them from boats, because the messiness of dependance on colonies could be greatly reduced. The invention of serviceable aircraft carriers, more than Franz Fanon, helped end classic-era colonialism.
There are 22 working aircraft carriers in the world. I bet it will not astonish you to learn that half of them belong to the US, and any one of the 10 Nimitz-class carriers we run are bigger than many of the rest of the world's carriers combined - and that doesn't even count our 9 smaller non-nuclear carriers that equal what passes for an aircraft carrier if you're Great Britain or India.
Because all 11 US super carriers are nuclear-powered, we not only don't need so many airfields around the world to enforce our hegemony, we don't need those pesky coaling stations either. Nuclear powered ships run for years before they need to stop for a refill.
China's Peoples Liberation Army Navy, with the Bondian acronym of PLAN, has been shopping in used carrier lots around the globe for ships to "study." They've been building and rebuilding conventionally-powered carriers, some of which are 50-60% the size of US super carriers. Then PLAN jumped the global hegemony line a little more by buying an unfinished Russian carrier, the Varyag, that Ukraine had for sale in one of those warship yard sales we don't hear about. Actually the story of the Varyag is worth looking into - it was purchased by a travel agency, I'm not making this up, then broke loose in a huge storm and went adrift, and was banned by the Suez Canal. Anyway, eventually the huge ship was fitted and refitted as a modern aircraft carrier by PLAN. The as-yet unnamed aircraft carrier has just returned from two weeks of sea trials. Here's a picture from an excellent blog, defensetech.org - a good place to go if you want to track the implements of our forthcoming wars.
So what, you may ask?
First: 34 years ago I heard futurist Hazel Henderson give a talk in Minneapolis in which she talked about the "last thrashing of the dying dinosaur." If our country's political system continues its substantial decomposition, if we continue to permit a great number of our citizens to live in seething poverty, if we continue to confuse cultural diversity with an acceptance of pugnacious communalism, and if we allow the commodification of the most intimate reaches of our values, families, art and music and religion and education - then there we'll be, a snarling tyrannosaur on its back. With 11 nuclear aircraft carriers in its thrashing tail. The mad joyrides of Rumsfeld and Cheney will be nothing compared to what we could do then.
Second: China is a country that seems to have a high degree of comfort with the use of the mailed fist to both deter and punish what it perceives as threats. China didn't buy the Varyag just for 2012, the year we're likely to see it commissioned with a new name. The Varyag can launch all sorts of aircraft - it also has various other ocean warfare functions, and an independent missile launch system. But PLAN is in it for the long haul. In 20 or 30 years, China could have a world class power projection fleet to oppose what of the Nimitz-class ships are still afloat, poorly maintained by the wounded dinosaur.
Given those two observations, here's the so what: the gravely wounded institutions of our struggling polity and culture desperately need our attention. More than the sleekest aircraft carrier, our greatest bulwark against future existential threats is repair and recovery of our country's internal life. And we don't live in a vacuum: we're are under more scrutiny by our rivals than by our own citizens. Our adversaries see our strengths and weaknesses, and are making detailed plans and investments to address them. Will we?