Is There Anything Strategic About 4% of GDP to Defense?

Below is the transcript of a Twitter conversation our Bloghost Galrahn and I had earlier today, in which I took issue with something he Tweeted.  For those of you who don't know what Twitter is, just pretend we were real people who have actual conversations: 

Galrahn: Romney is right, defense cuts aren't guided by strategy. But Romney's defense spending increases aren't guided by strategy either, so wtf
 McGrath: @Galrahn re: Romney no strategy. Have you read the White Paper the campaign issued? Not called a "strategy" per se, but certainly strategic
Galrahn:  @ConsWahoo Sir, there is nothing strategic about penning defense spending to 4% of GDP. That idea is an obscenity to strategic thinking.
 Galrahn:   @ConsWahoo when strategists make spending money on defense the "ends" of defense policy, strategic thinking is on holiday.
 McGrath:  @Galrahn answer my question. Or have you read his book "no apology"? You sir, are underinformed.

Galrahn:   @ConsWahoo i have read the paper, not the book. 

Galrahn, in my opinion, dismissed a good deal of interesting (dare I say, strategic) thinking about the role of the US in the world and a military that would pursue it with his 140 character swipe at the 4% notion.  Should you be interested, some of that thinking was laid out in the Romney Campaign's White Paper,

and in his book, "No Apology".

Putting aside Galrahn's dismissive attitude about Romney's defense and foreign policy (based seemingly on the 4% figure), he raises an interesting point--is there anything "strategic" about the 4% figure.  I'd never thought about it in those terms before today, but now that I have, I would like to make an argument that it is indeed strategic, but probably in terms that are unsatisfying to most military strategists.

1.  All defense strategies ARE SHAPED BY  resource decisions.  We purists wish that it were not so, but it is.  Sometimes those decisions are specific (as in "cut $487B from what you were previously planning to spend and shape a new strategy to do it), some are not specific at all.  But the REASON you have a strategy in  the first place is to lend priority to the money that you ARE given.  Strategy would be unnecessary with infinite resources, right?  You'd just buy everything you need and as many as you could man.  So if EVERY strategy FOLLOWS a resource decision, the question then is how is that resource decision made? 

2.  Some portion of our national treasure must be allotted to defense.  Sorry to sound like a Tea Partier folks, but providing for the national defense is right there in the Constitution as a DUTY of those who swear an oath to it.  This of course, makes it somewhat special in the pantheon of things upon which national treasure is lavished, but I digress.  What then, is not "strategic" about selecting a number in that range that serves the political purpose of setting a floor "investment" (love that word) in national defense?  Such a tie sends a (strategic) message to the Congress that states "here is my minimum"--just as it announces to the world the political will of the Executive to continue to tend to our globally dispersed knitting.  Additionally, setting a 4% (or 5, or 10, or whatever) sends the "strategic" message to one's own administration about what your priority is when it comes to OMB's juggling of the books each year.  Setting a floor and making it stick TIES THE HANDS of the bureaucracy.  

3.  Something is strategically better than nothing.  The Royal Navy's late 19th century strategic approach was to be larger than the next two navies combined.  My mentor and sage Frank Hoffman has suggested that we peg our defense spending overall to the spending of the next two highest nations combined, which in the present would be Russia and China.  He's not a fan of the GDP peg either.  I find his approach reasonable, and moderately strategic--but no more so than relating spending to the wealth of the nation.  In fact, there's a case to be made that his approach is LESS strategic, as it to some extent lets other nations dictate our spending rather than having our interests drive it.  And what is GDP but a rolled up measure of the national interests we have, visualized in economic terms? 

I think I would be far more worried if someone suggested there be a "ceiling" figure to peacetime defense spending, as that would tend to divorce such spending from a measure of our interest.  

So in the aggregate, and as someone who has earnestly dabbled in strategy, I find no offense in strategic political guidance from the Executive that sets a lower bound on thinking.  And please, save the 'you're just carrying the water for Romney" stuff.   Galrahn raised an important question, and I felt it deserved an answer.  Take issue with my logic (or lack of it) as you will.

Bryan McGrath