Answering the question “How will world events unfold?” is always difficult, as it involves predictions about the future. So consider the following as the outline of a military thriller, not a prediction about the future. You may have difficulties sleeping well if you take those speculations too seriously.

North Korea

The small impoverished autocracy between South Korea and China (with a short border with Russia as well) is currently the focus of attention as a prime candidate for Trump’s next war. The stated reason is that it close to be able to build nuclear weapons and Intercontinental Ballistic Missiles (ICBMs). A working combination of both is the entry ticket to the big boys club of nations that can play in the nuclear deterrence league. The capability to attack any relevant target on the planet with a nuke ensures that it is no longer feasible to go to open large-scale war with anyone playing in that league.

However, North Korea is currently not yet part of that club. Building a reliable ICBM is challenging and costly. An ICBM is essentially a space rocket that is used to shoot a warhead on a long arc through space with high precision to a target on earth. This is achieved by giving the payload not enough speed to stay in orbit, mostly through a worse weight to thrust ratio than needed for orbital velocity and different burn profiles. So roughly the same rocket system can be used to shoot a lighter satellite into orbit or a heavier warhead to a distant target.

One of the really difficult parts of an usable ICBM is the necessity to build a re-entry vehicle. This is the system that prevents the warhead from burning up from atmospheric friction during the re-entry from space and control its flight sufficiently precise to actually hit the intended target. North Korea has not yet even attempted to demonstrate a successful re-entry from space. Studying satellite images and chicken entrails, western experts guess that it will take them another couple of years before they can do that.

(Update 8. August 2017: The chicken entrails apparently were not that fresh anymore: the speed of development of the re-entry vehicle seems to have progressed faster than expected, but so far it is probably still not an operational capability. Thanks to @marasawr for pointing that out.)

So why are the other nuclear powers and especially the US so concerned now that they contemplate risking a war about a weapon that is apparently far from finished? My guess is that the reason is that North Korea has essentially already a somewhat realistic capability to threaten the US that does not need a re-entry vehicle: nuclear EMP. A nuclear EMP is an electromagnetic pulse caused by exploding a nuke outside the atmosphere, which converts the radiation from the detonation into an series of pulses of radio and magnetic energy of immense proportions. A nuclear EMP will destroy or at least temporary disable almost all modern electronics, power lines and wire-based communication lines — in a radius of several hundred kilometers. Satellites will be affected in various unpleasant ways as well.

The nuclear weapons needed for this effect are comparatively small. The actual tests conducted by the US and Russia in the 1960s were carried out with bombs below 1.5 megaton yield, some even much smaller. The strength of the pulse depends on the height (optimum seems to be around 200–400km) and the position of the target area within the earths magnetic field. The physics and particulars, once classified, are meanwhile widely known. Here is a collection of declassified videos from the US high altitude nuclear tests.

Fission bombs like the ones North Korea is working on, as opposed to thermonuclear fusion weapons that make up the bulk of the arsenal of the larger nuclear powers, are particularly suited for EMP generation due to their comparetively higher gamma radiation yield. There are apparently also ways to optimize for especially high gamma radiation with relatively simple means once the basic weapon design has been mastered. Especially for a low-tech country like North Korea this would seem to be a very attractive route to take.

The potential for a North Korean EMP-threat is well-known to US military planners. But for public consumption the storyline is reduced to the more simple “ICBM with nuke” threat, regardless of technical realities.

So what would an evil dictator need to zap parts of the US with an EMP? Obviously a nuclear weapon with a moderate yield and a working space rocket to fit it on. North Korea probably has the nuke, even if their last test was in the range of 20–30kilotons, which may limit the effect somewhat if not optimised for gamma yield. And the country has demonstrated at least once that it can launch a satellite into a somewhat decent orbit (in a surprising fit for this speculation their one successful satellite launch was into an orbit of 400–500km). The achieved launch weight however was a bit on the challenging side with an estimated 200kg orbit payload. Miniaturising an uranium fission bomb into that weight class might be beyond the current capabilities of the country so a more powerful rocket might be required.

So if we ride with this threat speculation for a moment Kim might already be able to pose a plausible threat of kicking large areas of the US back into the pre-digital area. But: there are countless technical problems that make such an attack at least fraught with difficulties and reliability problems. The warheads not only need to be miniaturised but also ruggedised. So far they have only been tested under lab conditions in mountain tunnels. They would need to withstand the vibration and acceleration forces during a rocket launch as well as the near vacuum and temperature conditions of a half hour space flight.

Kim Jong Un giving guidance on what looks like a realistic miniaturised implosion-type nuclear warhead mock-up.

Also, the rocket would need to work reliably and at least reach a halfway predictable orbit. I have the strong suspicion that the series of failures in North Korean rocket tests might not just be the result of the usual scientific, technical and quality assurance difficulties, but maybe also be due to clandestine US intervention. Inserting subtly failing parts into the adventurous supply chains North Korea needs to rely on due to the embargo or playing with the radio telemetry data during the rocket tests is certainly something the US is capable of. This would also match the interests of China, which controls nearly all supply lines to North Korea.

In normal times I would tend to conclude that this North Korea crisis ends like the previous ones. China uses its influence to prevent an all-out escalation, extracting some concessions from the US in the process, Kim postpones his nuclear tests and receives more food aid. Indeed, there are signs that this might be the intended outcome. An outbreak of hostilities between North and South Korea would be catastrophic for the South. Its densely populated capital Seoul is well within the range of North Korea’s conventional weapons like artillery and shorter range rockets. An EMP detonation located over the South would be absolutely devastating to the highly networked and digitised country while probably affecting the military capabilities of the North to a far lesser degree. China and Russia would need to cope with an wave of refugees from the North — which might be the reason for the massive army force movements by both countries into their border regions with the North reported recently.

(Update 3. September 2017: the official news agency of North Korea published a piece about Kim inspecting their new hydrogen bomb warhead. The interesting paragraph reads: “The H-bomb, the explosive power of which is adjustable from tens kiloton to hundreds kiloton, is a multi-functional thermonuclear nuke with great destructive power which can be detonated even at high altitudes for super-powerful EMP attack according to strategic goals.”)

But: these are not normal times. US president Trump urgently needs a serious distraction from his current domestic difficulties. And there is a confluence of interests elsewhere that make some sort of hostilities look attractive to another player: … Russia. Which brings us to a different world region (and even deeper into speculative territory).

The Persian Gulf

A frequently overlooked backdrop to what is really going on in the world is the price of oil. Saudi Arabia has been on a price-crushing oil pumping binge for quite some time, apparently with the dual goal of bancrupting US fracking companies and weakening Russia. There are two key charts that need to be considered for this part of the thriller plot. The first is average oil production cost in the various countries:

Source: http://cdn.static-economist.com/sites/default/files/images/print-edition/20160109_FBC031.png, The Economist

I have updated the current oil price (ca. $53) at the time of writing as a red line for convenience.

The second chart is the price of oil required to balance the national budget of the various oil producing countries:

http://static4.businessinsider.com/image/55acfb262acae7c7018b7e66/here-are-the-break-even-oil-prices-for-13-of-the-worlds-biggest-producers.jpg, Business Insider

The current oil price is below where this chart begins. Which means that none of the highly oil-dependent countries currently can balance its budget. Russia and the OPEC (read: the Saudis and Iran) have made a historic deal to bring the oil price up which succeeded to bring it at least to a level where Russia is not producing at a loss anymore and Saudi Arabia can cope without exhausting its currency reserves. However, the deal is valid only for 6 months and Russia still faces a serious budget deficit that can no longer be compensated by dipping into its reserves. For the Saudis $55 is a comfortable price, as it still forces the US fracking competition to pump at a loss and still weakens Russia, but at a slower pace. Something has to happen. And nothing helps the oil price like a proper war.

So Trump needs a war to distract everyone. Russia needs a war without much additional own cost — one without its direct involvement. Russia has apparently a lot of levers and influence on team Trump. Given the mounting evidence of russian influence on him and his cronies Trump can at the moment not easily deliver on promises made before the elections — especially lifting the economic sanctions against Russia. Otherwise he would have done so already. But what he can deliver without causing suspicion is a war that rises the oil price. And afterwards he could argue that in order to help the US economy that has been hurt by war-induced high oil prices lifting the sanctions is good for everyone. And maybe Russia will show itself unexpectedly helpful in the North Korea crisis…

There is an additional bit that caught my attention. In an analysis of the recent Iranian navy drills I found this intriguing sentence: Iran is practicing for a scenario where the U.S. is distracted by another conflict and is either unable or slow to respond to a threat in the Persian Gulf.

Now what would be such a distraction…?

The US Navy is currently stretched a bit thin on available aircraft carrier battle groups. The current fleet status board shows that there are three carrier groups that could in principle be deployed if needed. But they are all in the US and will need some time to arrive in the gulf (or North Korea) and might not be in optimal training state.

If for some reason hostilities would break out in the Persian Gulf and/or the Red Sea, oil shipments would come to a brutal stop for some weeks. Yemen, the current proxy battle ground between Iran and Saudi Arabia, is located at the Bab el Mandeb Strait, the entrance to the Red Sea. Iran has supplied its proxy group there at that choke point with anti-ship missiles. And the Iranian Navy just trained how to block ship traffic through that relatively small channel of sea.

I don´t think Iran would be so stupid as to block the flow of oil (including their own exports) unprovoked. They have better options — like using their influence in Saudi Arabia to destabilise the fragile balance of power in the country. But I can easily imagine a crisis escalation sequence that would lead to a situation where blocking a third of the world’s oil flow seems like an appropriate and logical next step. And Iran has been preparing for it.