The Quantum Mechanics of Defense Spending

The shorter Matthew Yglesias on 'the coming multipolarity':

1. Economically, the world isn't unipolar at all. You've got the US, the EU and to a lesser extent, Japan. The rest are all B-list countries and will be for quite some time.
   
2. Militarily the US is the undisputed number one. But even then, it's abilities are limited to whacking C-list countries such as Iraq or Serbia. Could the US have taken on Iran instead of Iraq? China? The EU?
   
3. Some day the US may decide to spend it's money on something other than maintaining the ability to whack C-list countries. I hear Bush has some plan with personal accounts?
   

And then comes the paragraph I take issue with:

The main thing to worry about, I think, is not that putative rivals will grow too strong, but that potential friends won't be as strong as they could be. American military spending should probably shrink over the medium to long term. It would be nice if that didn't just result in a global anarchy. If the other rich democracies spent a sum somewhere between what they're spending now and what we're spending now, then the overall capabilities of the free world would be enhanced, the burden on America lessened, and we could have a more even sharing of the decision-making, less crazy overreactions on our part, less resentments and blowback from elsewhere, and a bunch of other good stuff.

Ezra Klein says basically the same thing after reading Matt:

Later in his post, Matt says that we're eventually going to cut down on military spending. And I hope so, it's really the only economically rational option. If we stopped ensuring the firepower to confront every threat, other countries would have to build up a bit in order to fill the hole. That would reduce the cash they've got on hand and go far towards allowing our continued economic preeminence. Sadly, we've taken in with this strange ideology that blanches at multilateral cooperation and uses martial imagery, and thus military support, to win elections. Whether or not we can break that remains to be seen.

But that's not how it works! Other countries will not "build up a bit in order to fill the hole", nor will they start spending a sum somewhere between what "they're spending now and what we're spending now".

There are two ways to measure the size of a country's military. One is to look at the money going in as a percentage of GDP. The other is to look at the abilities of that military. What does the money buy? Can you:

1. Defend the homeland?
2. Whack a C-list country?
3. Command & Conquer?

Ad. 1. Defense. With the Chinese & Russkies less dangerous than ever, maintaining the EUs or Japan's defenses is pretty cheap.

Ad 2. Retaliation. Gunboat diplomacy. Whatever you want to call it. The French and the British still have that ability. But it doesn't come cheap. You need an aircraft carrier with a fleet. Preferably more than one aircraft carrier. And you need to keep this fleet technically superior to whatever the C-list countries can throw at you. It can be done, but it is more pride than common sense that makes the French and British actually do it. Besides, what if they want to whack a C-list country and the US says no? They pull out, that's what happens.

Ad 3. Regime change and a succesful occupation in a C-list country. You need a fleet, an airforce that can claim total air superiority in a piece of sky on the other side of the world, a very large army, lots of airlift capability, foreign bases in the region and probably other stuff I haven't even thought off. This takes years and years to build up, and will probably cost more than any C-list country is worth. And then what?

Why should the non-French, non-British Europeans make the jump from 1 to 2? Why should the French and the British make the jump from 2 to 3? It is simply not worth it.

Sure, the EU could in theory muster the finances to pay for a European military that could rival America's. But that's not bloody likely. The EU is a framework of nations. They wield vetos over stuff like this. Their citizens generally disapprove of any pan-European mushy initiative that isn't entirely symbolic.

India and China are each other's biggest rivals. They share a long and disputed border and have fought small scale wars over it. Why would India want to sail to China? Conversely, if China were to built a fleet, Taiwan and the US would go apeshit.

This kinda leaves Japan. With North-Korea and with increased business interests in China, Japan might actually want to upgrade it's "self-defence force" to an actual army. But Japan can't credibly threaten China (too big) or North-Korea (which has both missiles and nukes). Why bother with an uncredible threat?

The US is going to cut back on military spending. But the others can't just make up for it by adding a few tenths of a percent of GDP to their spending. There is nothing in that market niche that's worth buying.