Military spending data from this is provided courtesy of SIPRI. Check them out; they provide a wealth of data.
So let's just look at a simple bar graph. On the Y-axis we see the US's share of whatever it is we've labelled on the X-axis.
Imagine, for a moment, that every country has the same level of technology, and produces everything equally efficiently, so a dollar of military spending in Zimbabwe buys an equivalent amount of military might to a dollar of military spending in the United States. In this case, we're prepared to face off against a little less than half of the military spending in the world. Let's see what that looks like. Well, if we take the next 20 nations we pretty much get to spending parity. These nations are:
- China, P. R.
- Saudi Arabia
- Korea, South
Now, I grant that our military isn't designed to fight a 20 front war, but we sure spend like we are. Remember, I'm currently assuming that Greece, Turkey, Colombia, UAE, Korea, Brazil, India, Saudi Arabia, and China get an equal amount of military might per dollar as we do... yeah right. Let's put this another way, if China sextupled their defense spending next year, would we think that they were intending to maintain a purely defensive military? Hell no, we'd start trying to figure out which border state they were planning on expanding out into. It's clear that we do not have a fighting force motivated by defense.
But, you may say, we are currently in two notoriously expensive wars. Surely before those we had a more defense oriented military. Kinda? In 2000 we only spent as much as the next 10 largest militaries combined. It's also worth noting how many of these nations are credibly opposed to our national interests. By my take it is, arguably, China, Russia, Saudi Arabia, UAE, Colombia. Our allies greatly outnumber our "enemies" (and by enemies I mean trade partners or fellow UN security council members or nominal allies) in that list.
Okay, you may say, but what if the US was in a very high pressure situation with a lot of powerful enemies. What might an appropriate amount of spending be? Well, let's see, Israel is a major terrorist hotspot, an enemy to literally all of its geographic neighbors with whom it has been at war on several occasions in recent history, and an aggressive militaristic culture to boot. How does it spend compare to its neighbors? At a glance we see Saudi Arabia, UAE, and Turkey all spending more than Israel. Whatever we're doing, it ain't defense.