WITH North Korea's threatened withdrawal from the nuclear Non-Proliferation Treaty (NPT) due to take effect from Saturday, Pyongyang is exploiting the international alarm at its hardline position to extort concessions from the United States and South Korea. Both countries are - perhaps too complacently - signalling their readiness to be co-operative, provided the international community gets the assurances it wants. But they are rightly cautious about giving too much away in advance of any firm commitments from the other side.

The West wants Pyongyang to cancel its withdrawal and open its nuclear facilities to inspection by the International Atomic Energy Agency; it fears North Korea is on the verge of building a bomb. North Korea wants Western aid for its moribund economy, anend to US military exercises with its South Korean rivals and anything else it can extort without giving up its secret nuclear programme.

All this should make North Korea an international object of contemptuous laughter. But its reputation for barmy unpredictability puts it in a position to blackmail a hard bargain. The Americans are only too aware that the country's maverick Stalinist leader Kim Il-sung and his son Kim Jong-il are dangerous enough to withdraw from the NPT and develop nuclear weapons. What nobody knows is whether they are also mad enough to use them.