North Korea is no run-of-the-mill autocracy. It is a pure totalitarian state. Its military is the largest force per head of population of any in the world. Its brutality is evinced by credible reports of chemical experiments conducted on political prisoners. In developing a programme to enrich uranium since the late 1990s, it has breached the Nuclear Non-Proliferation Treaty, the 1991 North-South Denuclearisation Declaration, and the 1994 Agreed Framework with the US.

The hermetic state’s removal of seals and cameras from its Yongbyong nuclear facility is the latest in that series of provocations. And it presents an apparently intractable problem. Western diplomatic options are limited by the sheer extent of North Korea’s autarchy. Economic pressure and diplomatic isolation may be effective against an extremist state that nonetheless has a civil society and a degree of political openness, such as Iran. But they are chancier strategies against an absolute tyranny that is indifferent to the costs borne by its captive population. How to respond to such flagrant adventurism is made still more difficult by the secrecy surrounding the health of Kim Jong Il, the North Korean leader. The West cannot be certain whom it is contending with now, let alone who will be in power in 12 months’ time.

At a minimum, however, Western diplomacy must abstain from actions that would strengthen North Korea’s hand. Pyongyang has threatened to abandon the six-party talks concerning its nuclear programme. To promise economic benefits if it adheres to those negotiations would merely indicate that aggressive behaviour will earn its own reward. The message must be that there will be costs to non-compliance, and benefits to engagement — but that the current position, in which it is open at any time for North Korea to engage in extortion if its demand are not met, is unconscionable. There is little purpose in demanding merely that North Korea return to a suspension of its nuclear activities. It is clear that the regime will retain its prerogative to expel inspectors from the International Atomic Energy Agency when it is expedient to do so. Instead, North Korea must be presented with wider requirements, in return for substantial development aid and a peace treaty: revoking its nuclear programme, cutting its conventional forces, reforming its economy and dramatically improving its human rights performance. Any agreement of that type will not produce a civilised state; but it might initiate a process whereby North Korea would one day resemble the Vietnam of today more than the Cambodia of 30 years ago.

If no such agreement is accepted, then coercive threats must be credible, and exercised. That course is made undeniably more difficult by Russia’s withdrawal from talks to counter Iran’s nuclear ambitions. But Washington must seek to persuade China and Russia to block all transport routes for the export of North Korea’s nuclear materials and technology. And China and South Korea must be urged to suspend investment and trade relations with Pyongyang.

A strategy of economic coercion carries a risk of encouraging the paranoia of a recalcitrant regime. But the most important diplomatic task is to convince North Korea’s rulers that their brinkmanship will tip the regime towards collapse before it engulfs the region in catastrophe.