LEADING ARTICLE: North Korea is an exception that must not prove the rule on nuclear proliferation

NORTH KOREA would probably not claim to be in the business of winning friends and influencing people, at least not in the way Dale Carnegie meant it. This sad bastion of poverty-communism in north-east Asia threw a rhetorical fit yesterday and declared in a long statement from its foreign ministry that it would not be returning to the six-party talks on its nuclear programme. It added, almost by the by, that it had produced nuclear weapons for its own defence and would take measures to boost its nuclear arsenal "in order to protect its ideology, system, freedom and democracy".

Thus did North Korea appear to confirm what it has long hinted in private: that it has a nuclear capability and has no intention of giving it up. So now we know - or do we? The fact that North Korea boasts of having developed a nuclear weapon does not necessarily mean that it has. Bluff as a diplomatic weapon is not unknown from countries that feel beleaguered. Nor - even if true - does possession of a nuclear weapon necessarily mean that North Korea has the capability to use it. The only long-range missile it is known to have tested is thought to have swerved off course. It would be no less dangerous for that, of course, but not quite an accurate delivery system.

North Korea says that what prompted it to withdraw from the talks and brandish its weapons was its inclusion in a list of countries described as "outposts of tyranny" by the US. This was no way to treat a partner in dialogue, it said. Whether or not wounded dignity was behind North Korean pique, its action seems only to confirm its long-standing ambivalence towards the whole idea of talking about its nuclear programme at all. The question now is what the rest of the world, starting with the United States, is supposed to do.

The initial response was probably the wisest one: condemnation from around the globe, tempered with regret and hope - expressed without much confidence - that Pyongyang would reconsider. From Washington to Brussels, from Moscow to Beijing, this was the message conveyed. The US exuded calm, insisting that it had "assumed" since the mid-Nineties that North Korea had had the capability to produce "a few" weapons. The US Secretary of State, on the last leg of her European tour, went out of her way to reassure North Korea's neighbours and anyone else who might be concerned that the US and South Korea between them had a deterrent that was well able to deal with any potential threat.

As an initial reaction, phlegmaticism has much to recommend it. The regime in Pyongyang is unpredictable. The extent to which Kim Jong Il is in control is not at all clear. The economic situation is desperate; without international food aid, whole regions would be starving. Korea-watchers will pounce on Pyongyang's statement that it needs to protect its ideology and system as confirmation that North Korea is playing the nuclear card to bargain for its very survival. If this is so, the absolute priority must be to ensure a transition that is as orderly as possible.

That a regime such as North Korea's has been able to acquire a nuclear capability - even an unsophisticated one - should, however, be grounds for deep concern internationally. As should be the blackmailing use to which this capability is apparently being put. By withdrawing from the Nuclear Non-Proliferation Treaty and flouting all international nuclear regulations, Pyongyang has won a measure of diplomatic power which those with unrequited nuclear aspirations can only envy. This sends precisely the wrong message to a country such as Iran, which seems even now to be weighing the pros and cons of defying the NPT in pursuit of its own energy and security interests - and is feeling the heavy hand of European and US pressure as a result.

This is a conundrum the treaty signatories must address when they meet in May for their five-year review. North Korea may have won no friends. As for influencing people, though, that is a different matter.