Around the planet the world’s networked seismographs will have revealed in seconds all sorts of things about North Korea’s latest big bomb test, hydrogen or otherwise. Notably that it was indeed a bomb (and not an earthquake) and where exactly the test took place. Other instruments will be tracing the radioactivity released into the atmosphere, giving lots more information about which radioactive materials were used.

So, what exactly are the issues here? A handy summary.

Is it illegal under international law for a state to possess nuclear weapons?

No. A number of states have them. Some argue that using such an indiscriminate weapon of mass destruction would be (and indeed was) a war crime, but that is not the formal legal position.

What rules do apply?

The key text is the Non-Proliferation Treaty (NPT) from the 1960s. This was the first (and impressively successful) move to set a wide international framework for stopping the ‘proliferation’ of nuclear weapons. The heart of it was a strategic if not moral deal: if the then avowed nuclear weapons states (USA, USSR, UK, China and France) agreed to move towards full nuclear disarmament, the rest of the world would not develop nuclear weapons. New arrangements were brought in to allow the International Atomic Energy Agency (IAEA) to check nuclear energy and research facilities to make sure that no materials were ‘proliferating’ into the wrong hands or for the wrong purposes. Later a separate treaty (Comprehensive Nuclear-Test-Ban Treaty – CTBT) banning nuclear weapons tests was agreed in the 1990s.

The basic point is that peaceful nuclear work (eg nuclear reactors for generating electricity) is accepted by the international community as long as the IAEA is allowed to monitor what is going on within that programme. IAEA inspectors (many of whom I have met) roam the globe to visit civilian nuclear facilities and check what is happening there. If the IAEA have suspicions that something is not right (eg that illicit nuclear weapons research is going on and/or that nuclear material can not properly be accounted for), the international community gets very restless: if the world agrees on anything it is that no-one needs rogue nuclear weapons activity.

Seems good. Key issues?

Only states that have signed/ratified the NPT and CTBT are bound by them. Any state that has NOT signed the NPT is free to develop and possess nuclear weapons.Likewise any state that has not accepted the CTBT or NPT can develop and test nuclear weapons.

Israel, India, Pakistan and South Sudan never signed the NPT: India, Pakistan and Israel are all more or less openly now nuclear weapons states. India and Pakistan in particular argue that it is not fair that the original nuclear weapons states have continued with their nuclear weapons programmes for decades after the NPT was signed.

Many other states agree with that position but have not wanted the obloquy and likely intense sanctions arising from any move by them to develop nuclear weapons. The five original nuclear weapons states point to huge reductions in their nuclear arsenals since the 1960s and say that in due course further reductions are contemplated, and that current threats to international security justify them keeping their programmes.

So, North Korea..?

North Korea never signed the CTBT. It did sign the NPT but withdrew from the treaty regime in 2003 after US claims that it was cheating and developing a nuclear weapons programme. That means that under international law North Korea is within its rights to build and test nuclear weapons. North Korea is the only state ever to join then leave the NPT framework.

What about Iran?

Iran has signed the NPT and (unlike North Korea) has not left it, so it is within the NPT/IAEA scrutiny regime. Of course the world suspects that Iran is either (a) cheating and/or (b) doing everything it possibly can do under the NPT to have everything ready to develop and deploy a nuclear weapon fast should it ever decide to follow North Korea and leave the NPT regime. This is why Iran has come under heavy international sanctions because of its unclear nuclear programmes and ambitions.

Thus the Obama Iran deal. In return for sanctions being lifted, Iran scales back its nuclear programmes and allows a powerful international inspection regime that (in theory) is robust enough to ensure that Iran’s nuclear programmes are for peaceful/lawful purposes.

There are plenty of technical and policy reasons to criticise this deal, but its logic is at least plausible: given the available real-life options, it’s better to have Iran under a far stricter inspection system and (one hopes) part of normal international behaviour than not. Iran under current management of course schemes to use its re-emerging respectability and economic weight to manoeuvre (within the NPT/IAEA rules) ever closer to having a nuclear weapon ready to go as and when it decides the moment has come. The Obama Administration is struggling to maintain its credibility on all this.

Why not tough action against North Korea?

North Korea is under agreed international economic sanctions. But it also does an astonishing job at staying out of normal international processes – it sanctions itself through its sui generis paranoid communist isolation. Whereas it’s possible to imagine military scenarios under which (say) Israel launches a devastating attack on Iran’s nuclear facilities, no-one knows how to attack North Korea’s programmes in a way that will stop North Korea in turn blowing up plenty of cities in South Korea using nuclear or non-nuclear weapons.

Nor is it clear (a) what the world might offer North Korea in return for ending its nuclear weapons programme and returning to the NPT fold with a strict IAEA inspection regime, and (b) how any such offers might be sequenced in a way that North Korea might accept. Plus the very ‘rogue’ nature of the North Korean regime allows it to threaten to proliferate nuclear weapons material and technology to anyone willing to pay.

This explains the craftily ambiguous formulation used by President Obama when he met South Korea’s President Park in October:

Today, President Park and I are reaffirming that our nations will never accept North Korea as a nuclear weapons state.  We will continue to insist that Pyongyang must abide by its obligations on the complete and verifiable denuclearization of the peninsula in a peaceful manner.

What does ‘accept’ mean here? Does it mean that North Korea’s is ‘unacceptable’ in a practical sense and that the two sides will do what it takes to make sure that North Korea does not become a nuclear weapon state? Or does it mean that even if North Korea is within its rights to have a nuclear weapon and indeed gets one (as it is not under the NPT) this fact will not be ‘accepted’ legally and/or politically (whatever that means)?

One way or the other, it looks pretty lame now. Hence Presidential candidate Senator Rubio weighing in quickly now:

“I have been warning throughout this campaign that North Korea is run by a lunatic who has been expanding his nuclear arsenal while President Obama has stood idly by. If this test is confirmed, it will be just the latest example of the failed Obama-Clinton foreign policy … Our enemies around the world are taking advantage of Obama’s weakness. We need new leadership that will stand up to people like Kim Jong-un and ensure our country has the capabilities necessary to keep America safe.”

All good stuff. But what else specifically might be done, even if the UN Security Council wants to agree to Do Something?

Could the NPT collapse and lots more countries acquire nukes?

Unlikely. The Iran deal shows that the NPT/IAEA approach remains robust – few states want to go through the fearsome economic sanctions that Iran endured while trying to cheat the NPT regime, and even Iran did not dare simply walk away from the NPT. Similarly the North Korean economic and political development model outside the NPT is unattractive to any state with a brain. Why invest in all that incredibly centralised and high-profile hassle when there are so many cheaper and unobvious ways to cause an enemy state mischief, eg through cyber-attacks?

But there again, who knows? The renewed tensions between Saudi Arabia and Iran may be prompting the Saudis to wonder if they need some extra heavy fire-power to deter Iranian threats. Oh, and the Iran/Saudi cris also does nothing to help take forward either the Iran nuclear deal or the Syria peace process. Elsewhere Ukraine must be bitterly regretting its decision in the early 1990s to return USSR nuclear weapons to Russia in return for what have been shown to be worthless Russian assurances on Ukraine’s international borders.

The most dangerous immediate risk is nuclear weapons technology proliferation from eg North Korea or Pakistan to ISIS or some other ‘non-state actor’ determined to boost its weight. In the great scheme of things, nuclear weapons are not that hard to make – after all, they were developed 70 years ago, well before email. The complexity lies in developing one unnoticed and then having the capability to deliver it against a target. That alas might not need a huge rocket programme – something small and dirty could cause staggering panic if exploded in a major western city.

Hmm. Conclusion?

As usual, all very difficult, with one problem feeding into another and no sense that any global grown-ups have a real grip. But broadly speaking the North Korean nuclear test of whatever bomb was tested does not change much in the short term as far as the North Korea problem as such goes, other than to give opponents of Obama/Clinton plenty more rhetorical ammunition.