THOUGH now behind schedule, negotiations on a treaty that would ban nuclear testing can still be completed in time for fall approval by the United Nations, according to the senior-most United States arms-control official.
"We didn't get as far as we would have liked," acknowledges US Arms Control and Disarmament Agency director John Holum, commenting on talks in Geneva, which adjourned March 29. "But I still think a treaty is doable because there is the will on the part of the member countries to make it happen."
The latest round of negotiations at the 38-nation Conference on Disarmament ended with no agreement on the key issues that block conclusion of one of the most significant arms-control treaties of the nuclear age. Breakthroughs will have to be made in a seven-week session beginning May 13 if the conference is to meet its goal of submitting the treaty for approval to the UN General Assembly in September.
During the six-week recess, negotiators will be poring through a new draft "model treaty" submitted last month by the Netherlands that, as Mr. Holum notes, "points the way to a final treaty and highlights the areas where agreements will need to be reached."
The key differences concern the scope of the treaty and whether it should be linked to a general timetable for nuclear disarmament.
THREE of the five "declared" nuclear powers, the US, Britain, and France, favor a "zero-yield" ban that would outlaw all nuclear explosions. China insists the treaty should permit so-called "peaceful nuclear explosions" for mining and heavy construction projects. In a meeting later this month with Russian President Boris Yeltsin, President Clinton will try to persuade Moscow to go along with the zero-yield option, thus isolating Beijing on the scope of the treaty.
In a move opposed in all five capitals, India is insisting that the declared nuclear states agree to a schedule for dismantling their nuclear weapons as a precondition to supporting the test-ban treaty.
As an "undeclared" nuclear power and an influential nonaligned state, India has considerable weight in Geneva. But the five declared nuclear countries insist on keeping their existing nuclear arsenals intact and preserving the means - including the right to conduct so-called "sub-critical" tests that release no radioactive material - to ensure their reliability.
"A test ban is a step forward on the path towards disarmament," says Holum, in an interview. "It doesn't make sense to refuse to take this step because it isn't the final step."
The other major sticking point concerns the basis on which unannounced, on-site inspections can be conducted to verify compliance. The job of verification will fall to a treaty-implementing organization created by the treaty. The US wants to use its own intelligence sources and not rely on the less-sophisticated monitoring system established by the new body.
"What we've seen in Geneva is an enormous determination to finish this task and not get bogged down in other issues," Holum says. "We have a very credible basis for moving ahead."