George bush was not pulling his punches. In a definitive policy speech earlier this year on preventing the spread of weapons of mass destruction, the US president declared : "The greatest threat before humanity today is the possibility of secret and sudden attack with chemical or biological or radiological or nuclear weapons.

"America will not permit terrorists and dangerous regimes to threaten us with the world's most deadly weapons," he went on. "We're determined to confront those threats at source. We will stop these weapons from being acquired or built. We'll block them being transferred. We'll prevent them ever being used."

The US position, it seems, could hardly be clearer. So how to explain, and how conceivably to justify, a little-noticed demarche last week by Mr Bush's officials at the UN conference on disarmament in Geneva? What the US did, in effect, was to torpedo a new global treaty banning the production and supply of materials essential to the building of nuclear weapons.

It is known as the fissile material cut-off treaty. It has been under discussion for years, strongly supported by Britain and the EU. Its main aim is to strengthen the nuclear non-proliferation Treaty (NPT), the cornerstone of the international effort to curb the spread of WMD. It is specifically aimed at nuclear-armed states such as India, Pakistan and Israel which are not party to the NPT.

But by seeking a global halt to the production of highly enriched uranium and plutonium for weapons, its wider overall aim is to reduce the chance of such materials being obtained by irresponsible regimes or non-state terror groups.

While dismaying, the Bush administration's stance was not totally unexpected. Bill Clinton backed the fissile material treaty in 2000, but once in office the Bush administration dragged its feet. Last year in Geneva it announced a review of its position, thus delaying further talks.

Last week the US ambassador to the conference, Jackie Wolcott Sanders, finally gave the go-ahead for negotiations, but with a fatal caveat attached. The US would back the treaty in principle, but it would not support the inclusion of binding monitoring, verification and inspection provisions.

A state department statement said the proposed inspection regime "would have been so extensive that it could compromise key signatories' core national security interests, and so costly that many countries will be hesitant to accept it".

But as the US knows very well, any new treaty is all but unenforceable without effective monitoring and verification. Inspections are essential, say arms control experts, if such treaties are to work. That is a view with which the British government, for example, wholeheartedly agrees.

"We believe that such a treaty should be established. We support it. It is a useful step towards curbing global proliferation," a UK Foreign Office spokesman said the other day. "We continue to believe it should be verified. We do not take the same position as the US."

In private, officials are hard put to conceal their disappointment at the US stance. Stated American concern about security and cost does not wholly explain it. At the nub of the issue is Washington's fundamental objection to opening up American military bases and industrial plants to international, especially UN, inspection.

For the neo-conservatives and ideologues around Mr Bush this is a visceral objection - even a matter of principle. Put plainly, they appear content to place the safeguarding of an uncompromised, untrammelled American sovereignty ahead of effective global arms control. -Dawn/The Guardian News Service.