Halting nuclear spread: US must lead

Six years after passage of the Nuclear Non-Proliferation Act (NNPA), which prohibited major nuclear export to countries that posed proliferation risks, the United States faces a critical choice: Should it go all out to get other suppliers to adopt similarly restrictive export policies, or should it respond to growing foreign sales by promoting its own nuclear exports?

To the delight of the nuclear industry - but in clear violation of the intent of the NNPA - the Reagan administration has chosen the latter path. Indiscriminate nuclear sales are justified on the grounds that they are essential to ensuring an image of the US as a ''reliable supplier.'' Besides the widespread availability of nuclear goods and services makes unilateral restrictions futile.

Clearly the US cannot unilaterally halt the spread of nuclear weapons; no one has ever endorsed such an approach. The NNPA was simply a first step toward multilateral restraint on nuclear sales. But the Reagan administration's tragic refusal to view the law as anything but a handicap for American exporters has created a self-fulfilling prophecy where foreign suppliers continue to promote and expand their nuclear sales.

Meanwhile, the administration has used loopholes in the NNPA to again promote our own nuclear exports. It has approved the sale to Argentina of 143 tons of heavy water, a critical substance for that country's sophisticated nuclear reactors. It has given Westinghouse permission to bid on a management services contract for a South African nuclear facility. It has licensed the export of thousands of ''dual use'' items with potential nuclear application - including a number with stated nuclear end-use - to countries that have resisted international non-proliferation efforts.

Where the law categorically forbids US exports, the Reagan administration has helped other suppliers fill the gap. While the NNPA required the termination of US fuel exports to India, the administration actively encouraged France to provide an alternate supply. In a similar situation with Brazil, the administration blessed a supply arrangement with the British, Dutch, and Germans.

The spread of nuclear weaponry will not be halted by a US export policy that includes only vague expressions of non-proliferation goals. Nor will it be halted by a policy of encouraging our allies to make sales we cannot. Precisely the opposite response is required: We must further restrict our own exports of nuclear technology and press other suppliers to do the same. A multilateral response to the problem is essential, but we cannot expect our allies to follow a lead we are not prepared to assume.

Last fall, the House of Representatives passed an amendment I offered that is an important first step in this effort. The amendment would require acceptance of stringent ''full-scope safeguards'' as a prerequisite for purchase of any US nuclear technology. A more comprehensive bill introduced by myself and cosponsored by 52 members of Congress would go even further to close loopholes in existing law.

But what is most immediately required is a firm commitment from the administration to forcefully confront the issue. The President must demonstrate through advocacy and action that he regards proliferation as one of the most important problems the world faces. Unless our government shows that it believes there is no nuclear sale to a potential proliferator that is worth the price, it will be difficult to convince other suppliers to restrict their own sales. This kind of multilateral restraint - achieved through serious and intense diplomatic effort - is exactly the second step that must be taken.

Diplomatic initiatives in the non-proliferation arena cannot succeed without active pursuit and leadership by example. As we enter a year critical to domestic politics and the international arms race, we must promote our interest in non-proliferation without equivocation. As new diplomatic opportunities arise - such as the possibility of negotiations with the newly elected Argentine government - we must seize them without hesitation. While we surely cannot single-handedly stop the spread of nuclear weapons, no country is better positioned than the United States to make a real difference.

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