The US Is Making Military Promises It May Not Want to Keep

Last week, North Korea lit off a nuke and put the global community into full-on denunciation mode. As part of the global response, the US sent a nuclear-capable B-52 bomber to saunter through the neighborhood, signaling that, indeed, two can play at that game, and North Korea better have a long, hard think about whether it wants to get into a nuclear slap fight with the United States.

Along with the fly-by, there's been an uptick in discussion about sending more US military stuff to the region, both to back up the US's buddies in South Korea and to give the guys in North Korea some pause should they have any bright ideas about crossing the Demilitarized Zone, or DMZ. In other words, classic deterrence.

The US military already has a ton of military presence in South Korea. There are about 28,500 American troops there, alongside nearly 650,000 South Korean soldiers. But is 28,500 a lot of troops? Compared to what? What's an extra squadron of jets supposed to do? Is Kim Jong-un sitting in front of a giant spreadsheet, running the numbers? Once he heard the news reports, did he decide to pick up the phone to tell his top generals, "Nope, guys, it's all off. The US says they might send another dozen jets, and I just can't take that risk, so I'm going to nix the invasion of South Korea. Anyone up for some bowling instead?"

Related: Kim Jong-un Basically Told the US to 'Come at Me, Bro' During a Huge Military Parade

If it all got real in Korea, you can bet that those 28,500 guys wouldn't be lacking for company. The whole of the US military would get spooled up to help out their South Korean buddies against the 1.2 million men of the North Korean army.

That is to say that the current US military force in South Korea isn't intended to really stop the whole of the North Korean military all by their lonesome, but rather to function as a tripwire of sorts.

There's a little bit of ambiguity when it comes to the precise definition of "tripwire." In some tellings, a tripwire literally means troops right up on the DMZ in little outposts scattered along its length, the theory being that any attack on the DMZ would mean killing US soldiers, thereby precipitating an American reaction. But in this case, I'm using the term tripwire a bit more broadly to mean US troops that would be caught up in the fighting, even if they aren't necessarily physically located right on the DMZ itself. Either way, if the bad guy comes in with enough force to completely dislodge the deployed troops, then that would be a sign for the rest of the US military to show up ASAP and get to the business of fighting a great big war. In essence, the purpose of the relatively tiny tripwire force is to die gloriously and call for their brethren to come and avenge their deaths.

In practice, tripwires are thought to be an antidote to the sort of invasion-by-inches thing that Russian President Vladimir Putin pulled off with the onslaught of Little Green Men during the Great Crimean Heist of 2014. Essentially, having tripwire forces in place bullies your opponents into more obvious tactics, giving you the edge and allowing you to stop them in their easy-to-see tracks.

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Getting back to Korea, even if there was a real, full-blown throwdown, it's unlikely the US would send over all of everybody. Even at the height of the fighting in Iraq and Afghanistan, the US didn't scour the cupboards and send everyone. Some of those forces were being returned from the war so they could take a breather, get replenished, be retrained, and so on. Moreover, the US has other military commitments around the globe that require troop presence.

Think of it like your bank account. Let's say it's payday and, with some luck and discipline, you've finally got yourself a thousand bucks to play with. Hooray! Now, you've got most of your bills taken care of, but you also know that you've got a lot more stuff that you need to get done sooner or later (preferably before it goes from bad to worse), like that thing with your tooth. You might be able to cover a couple of those major expenses, or maybe three of the smaller ones, but if you had to fork out enough cash for three big bills at the same time, you'd be hosed. And heaven forbid an emergency crops up — then it's all over.

Force planners are in a roughly similar situation. Let's say Russia gets grabby in Europe, and all of a sudden the US needs to scramble a few hundred thousand guys, then North Korea gets some clever ideas about hosting their very own #OccupySeoul event and the US needs to send everyone else to go fight. Now, what happens if China gets all stroppy about Taiwan? Or if Iran gets up to something? The US would be flat tapped out of forces and unable to deter anyone else from redrawing their local borders to their liking.

Watch VICE News' On The Line: Keegan Hamilton Discusses North Korea

When you think about it, the first and second would-be attackers may be dissuaded from picking a fight. But if the US already has its hands full with two big fights, it would pretty much be a field day for contestants three, four, and five. At that point, we might get all too clear an understanding of what wars and conflicts have been simmering under the surface for the last several decades.

In the most nightmarish (but probably pretty unlikely) of scenarios, the breakdown of international order devolves into some sort of appalling cross between World War III and full-on rioting: All the first responders are tied up and it all turns into smash-and-grab window shopping on an international scale.

There are already some historical analogies for this in other sectors. This scenario is basically like a run on the banks. Depositors go to the US-backed bank of security guarantees, and want to make a withdrawal of US military support. But once enough folks get nervous and start to demand their chunk of protection, it kicks off a feedback cycle. Soon, everyone is panicking, there's a run on US military forces, and disaster looms just around the corner.

Now, the Pentagon doesn't spend a lot of time talking about what they plan to do if everything goes straight to hell and multiple crises erupt, but let's make a few educated guesses.

One option (supposedly) available to the US is a whole raft of reliable and faithful allies who will step in and contribute when and where needed. But don't forget the fact that a number of countries have let their military atrophy while hanging out under the umbrella of US security guarantees, and may not be up to the task when things really hit the fan. The takeaway is that the US should be very supportive of increased military spending by its allies.

A second possibility is that the US could just try to drag out however many different wars across the globe and grind through them one at a time. But the history of the last decade has given a pretty clear indicator of what the US tolerance is for extended engagement. Now imagine that it was a decade of fighting that produced a few thousand casualties per month instead of that many over a decade, and maybe the idea of trying to outlast the chaos is a bit less appealing.

Or, there's always the nuclear option. If push came to shove, the US could fight and win a dozen medium-sized wars at the same time — provided that 11 of those were fought with nuclear weapons. The downsides to this option go without saying.

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Sure, this all might simply be anxiety about imaginary boogeymen. Maybe the bad guys are a lot nicer and more easygoing than the Pentagon fears and they'll just leave everyone alone even when no one is looking. But then again, maybe not, and what happens if you're wrong?

Which brings us back to the B-52 flyby. It's a near certainty that the message that the US wanted to send was one telling North Korea that they shouldn't even think about nuking anybody, and if they do, they're playing with fire. However, the more subtle point that goes with the threat of nuclear war is that the US has guaranteed the security of way more countries than it can plausibly defend at the same time. And in the (admittedly unlikely) event that all those outstanding bills came due, the world's lone superpower might find it doesn't have super powers after all.

Follow Ryan Faith on Twitter: @Operation_Ryan