Leading Article: A good deed with dubious motives

NUCLEAR proliferation is not an obvious field for humour. Yet there is something at least richly ironical in the story, sketched out on Wednesday by President F W de Klerk, of how South Africa's white government built six nuclear devices - only to realise that they were in danger of falling into black hands when democracy was finally extended, in whatever form, to South Africa's majority population. Thereupon, the said bombs, allegedly never tested, were dismantled. It is the first known case of a country with a nuclear capability willingly renouncing it.

South Africa's bomb is also unique in being not principally a deterrent but a weapon of blackmail (in this instance perhaps more suitably called whitemail). It was developed when the country apparently feared an attack by Soviet- backed forces from neighbouring countries, especially Angola and Mozambique. As Mr de Klerk explained on Wednesday, the idea was that if the situation became serious, one of the major powers - 'for example, the United States' - would have been told of the existence of South Africa's weapons in an attempt to persuade them to intervene. Pretoria's logic was presumably that dropping bombs on a black Soviet client state would have risked triggering a nuclear war.

All this shows just how paranoid President P W Botha's government became in the Eighties. In reality, South Africa's pariah status worldwide was of inestimable propaganda value to the Kremlin. To have invaded the country and overthrown the apartheid government would have been unthinkable. So, although the existence of South Africa's nuclear capability was always suspected, few strategists could discern a clear 'concept of operations', as defence specialists like to call it, except perhaps against a wildly improbable amphibious assault on the Cape.

Most countries that have developed or are developing nuclear weapons face an obvious potential adversary whom they wish to deter. In the case of India, it was China and, later, Pakistan, which duly reciprocated. North Korea, believed to be nearing nuclear capability, is palpably nervous of the economically dynamic and US-backed southern half of the peninsula. In addition, it is ruled by a autocrat of questionably sound mind. Israel has had good reason to fear for its existence: its nuclear programme helped to justify Saddam Hussein's programme (luckily nipped in the bud) to give Iraq a matching capability.

Any examination of the deterrent capacity of nuclear weapons leads to the contradiction at the heart of attempts to prevent their proliferation. If the possession of nuclear weapons by the old nuclear powers has helped prevent major conflicts between them, why should other nations not benefit in the same way by acquiring a similar deterrent?

The answer must be that deterrence works when nuclear powers are governed by rational leaders who wish to sustain the status quo. It cannot be counted on to restrain revolutionary governments bent on spreading the word by the modern equivalent of the sword. So it would be unwise to expect South Africa's commendable act of renunciation to be emulated. In this, as in so many other respects, South Africa was and remains a special case.