And even if you believe that drone strikes in Yemen, Pakistan, Somalia, etc., are making us safer from terrorists (I personally think the opposite), they don't account for that much of the military budget--and in fact many of them are conducted by the CIA, not the Pentagon.

As for the navy: What threat to America are American ships half a world away from our shores fending off? If the navy were 90 percent--or even 80 or 70 percent--of its size, who exactly would attack us? What vital interest would be threatened?

Some people say Middle Eastern oil is a vital national interest, so we must be poised to intervene if it is somehow threatened. But what form would that threat take? Even if oil-rich Arab nations were taken over by regimes so hostile to the US that they wouldn't sell it oil, that wouldn't much matter. The market for oil is global, and so long as oil producers sell their oil to someone--which is something oil producers tend to do--that will keep the price America pays for oil more or less unchanged.

There is, to be sure, one way our naval presence in the Middle East could affect our national security--but not in a good way. The fact that the Fifth Fleet is headquartered in Bahrain leads the American government to look the other way when the Bahrainian government suppresses dissent. And, as you may recall, siding with authoritarian Arab regimes is one thing that fomented enough hatred of America to turn terrorism into a national security threat in the first place.

And what exactly is our Pacific Fleet for? Don't get me wrong. It would bother me if China used its muscle to take possession of a few islands that rightfully belong to some other nation (assuming they do). And if our ships are discouraging that (which they may or may not be doing--I honestly don't know), I guess that's a good thing. But it's not a thing with direct bearing on our national security. And right now I'm just asking how much of what our military does actually makes the United States of America safer.

I want to emphasize that I'm literally just asking this question. I haven't conducted a big study on the subject or systematically thought the matter through. Maybe people will reply to this post in ways that convince me that, actually, something close to the current level of Pentagon funding is critical to our national security. Or maybe they'll fail to. Either way, it's a debate worth having, and if the fiscal cliff causes us to have it, then there's something to be said for fiscal cliffs.