Grand deal with N Korea beats hollow talk The world's policy towards North Korea is now very much like Robin Williams" joke about how Britain's unarmed policemen try to apprehend criminals: "Stop! Or I'll shout stop again. No sooner had Pyongyang made its third nuclear weapons test this week than the UN pulled off its best impression of a British Bobby by threatening to pass a "swift, credible and strong resolution" in response. That should really hurt. In his State of the Union speech, Barack Obama used equally hollow language, saying North Korea's "provocations ... will only isolate them further." This is a bit like telling J.D. Salinger that, if he doesn't behave, you'll be forced to ignore him completely. The truth is that, when it comes to North Korea, the world has run out of good options. This week's test suggests that Pyongyang's scientists are getting better at making smaller and more powerful weapons. North Korea's state media hinted it may have used highly enriched uranium as the bomb's fissile material, which would be an alternative to the plutonium it deployed in previous tests. In December, Pyongyang finally managed to put a satellite into orbit, beating Seoul to the punch. All the evidence suggests that Pyongyang is edging closer to its goal of producing an intercontinental ballistic missile capable of carrying a nuclear warhead as far as the US. This could still be years away, although Pyongyang appears to be progressing faster than many expected. There is also credible evidence of nuclear co-operation between North Korea and Iran, long collaborators in missile technology. An article in The Jerusalem Post suggested that Pyongyang may have tested this week's device on behalf of Tehran in the presence of Iranian scientists. You don't need to believe Iran has outsourced its nuclear programme to North Korea to think the threat of proliferation has increased. One thing seems clear. The current sanctions regime isn't making much difference. Even very poor countries, it turns out, can make nuclear weapons. Stephanie Kleine-Ahlbrandt of the International Crisis Group says of Pyongyang's "military first" policy: "They would eat grass for a hundred years if they could have a nuclear deterrent." If anything, sanctions may have pushed the regime deeper into criminal activity and weapons proliferation as a way of earning foreign currency. If the west so chose, there are probably ways in which it could turn the screws still tighter. One would be to revive the financial sanctions so effectively imposed by the US Treasury in 2007, although Pyongyang may be less vulnerable to such tactics than it was then. Another would be to mount some sort of naval blockade to intercept ships travelling to and from North Korea. Washington has shied away from both, partly because such measures would not really bite unless China also took part. That is most unlikely. China supplies North Korea with oil. Last year it had roughly $6bn of bilateral trade with the country, accounting for some two-thirds of North Korea's trade, no mean sum for an economy with a total output of just $40bn. If anything, China has increased its economic engagement with Pyongyang in recent years, granting visas for thousands of North Koreans to work in China (and remit wages) and investing heavily in infrastructure that will allow it access to an estimated $6tn of North Korean mineral reserves. There are signs, it is true, that Beijing is losing patience with Kim Jong-eun, the country's missile and Mickey Mouse-loving new leader. After December's rocket launch, Beijing unusually backed a UN resolution on tighter sanctions. It warned Pyongyang against conducting a third nuclear test and this week scolded it for going ahead, expressing - in a phrase that would stop any British bank robber in his tracks - "strong dissatisfaction" at Pyongyang's defiance. Beijing has even come under pressure from its own netizens who can't understand why it allows itself to be humiliated by its small and impoverished neighbour. Yet, when push comes to shove, China will not jeopardise the existence of a regime that stands between it and a reunified Korean peninsula hosting US troops. Beijing would prefer to have a nuclear North Korea on its doorstep than a collapsed state, a policy that one Chinese blogger likened to "keeping a crazy dog to guard the house." That leaves few choices. Andrei Lankov, a North Korean expert at Kookmin University in Seoul, argues in Foreign Policy this week that Pyongyang is already effectively a nuclear state. The "pipe dream of denuclearisation," he argues, is over. If that is right, the most than can be expected from Pyongyang is a nuclear freeze. Having witnessed events in Libya, Mr Kim is well aware of what happens to leaders who trade in their nuclear toys. All that remains then is to strike some sort of grand bargain: money and a security guarantee in return for verifiable limitations on the size of North Korea's nuclear arsenal. It would be a horrible deal, tantamount to giving in to extortion. Nor could Pyongyang be remotely expected to play fair. But short of a military campaign aimed at toppling the Kim dynasty - a policy for which no one has shown the slightest appetite - it may be the very best one can hope for. If anyone has a better idea, just shout.