It took only a few seconds for the father of the US atomic bomb, Robert Oppenheimer, to confront the implications of his actions. “Now I am become death, the destroyer of worlds,” he famously observed, when the first device was detonated above the New Mexico desert on 16 July 1945. But it took almost 20 years before the concerns of atomic scientists at the potential destructive force of their science — concerns that crystallized into a powerful movement against nuclear proliferation and atomic testing — saw their first political fruits in the partial Test Ban Treaty of 1963.

Ironically in the light of recent events, Oppenheimer was quoting from the Hindu scriptures. The Indian nuclear tests of 11 and 13 May this year have few redeeming features. In themselves, they will not give India the international status it craves, nor will they do anything to encourage the five established nuclear powers to disarm. The best that can be hoped for in the circumstances is that Pakistan's security is assured by its allies, and that peace holds until both India and Pakistan are brought into global treaties that will ultimately diminish their dependence on nuclear weapons.

This process will require the United States, Russia, China, France and Britain belatedly to adhere to their own treaty commitments and take genuinely significant steps to cut their nuclear stockpiles. Meanwhile, scientists associated either directly or indirectly with the development of the Indian bomb should take advantage of their current prestige, and press their government to behave responsibly. Initial bellicose comments last week about Indian intentions in Kashmir indicate just how difficult that will be.

Indian politicians are not unique in their adulation of nuclear weapons. In the United States, advocates of the Comprehensive Test Ban Treaty (CTBT) remain locked in battle with those whose basic instincts lean towards attaining nuclear superiority. Until two weeks ago, treaty opponents were arguing that ratification of the treaty was of no urgency, and could wait for a decade or so while US scientists figured out how to keep bombs working without testing them. Now, these opponents claim that the treaty — which India has not signed — is discredited.

The main concern of such opponents is their refusal to accept that foreign governments will adhere to treaty obligations. This point of view may have served the United States well during the Cold War. But it is insufficient for the security challenges of the coming century. On 10 June, Madeleine Albright, the US Secretary of State, will deliver a major address in Washington DC on arms control. Despite widespread nervousness about the Indian tests, these only add to the case for the treaty, and it is to be hoped that Albright will use the speech to press for its immediate ratification.

US scientists should support the administration in this endeavour, and then press for the deep cuts in nuclear weapons stockpiles advocated last June by the National Academy of Sciences (see Nature 387, 752; 1997). In India, nuclear scientists should capitalize on their new prestige in a bid to persuade their political masters to behave in a responsible fashion that, it is to be hoped, will now include signing up to the CTBT. Having been heroes for a day, they will discover that nuclear restraint is harder to achieve than nuclear criticality.