President Clinton will ask the Senate to ratify an international treaty that would ban nuclear-test explosions for all time.
Although there is wide support for the Comprehensive Test Ban Treaty (CTBT), strident opposition from conservative Republicans will likely trigger a full-blown debate over America's post-cold-war nuclear weapons policies.
Since the end of the cold war, there have been increasing calls for an overhaul of these policies. The latest came last month from the National Academy of Sciences, which urged major cuts beyond those already proposed for the arsenals of the United States and Russia. The two nations are now reducing their deployed warheads to about 5,000 apiece and have agreed in March to seek a new treaty that would slash them to 2,500 each. The academy also recommended that the former rivals forswear the use of nuclear weapons in first strikes or in retaliation for chemical or biological strikes.
Conservatives, however, insist the US must retain a powerful nuclear arsenal, citing an uncertain international climate and a possible renewal of tensions with China or Russia. Further, they argue the CTBT won't inhibit nuclear proliferation and can't be verified effectively.
The treaty would be enforced by means of a globe-spanning network linking treaty members' seismological systems and other detection facilities. Shock waves caused by a nuclear test anywhere in the world could be detected and reported, although even supporters agree small-scale blasts might escape detection.
CTBT critics also contend the US arsenal's reliability depends on periodic test explosions to ensure warheads can withstand aging well beyond their design life spans. The US stopped producing new weapons in the late 1980s and unilaterally halted test explosions in September 1992. Russia has observed a moratorium since 1990, while France and China declared similar halts after conducting nuclear tests last year.
Earlier this year, the US launched a $40 billion program to develop, over the next decade, high-speed computers and other means of simulating test blasts. As part of the Stockpile Stewardship and Management Program (SSMP), the US today was set to conduct a "subcritical" underground explosion at the Nevada Test Site - meaning it uses less nuclear material than is required for an atomic chain reaction.
The administration says such experiments, which are permitted by the CTBT, will help ensure the reliability of the existing nuclear arsenal. Some critics, including some scientists at the nation's nuclear weapons laboratories, have grave reservations about the SSMP, saying there can be no substitute to full-scale test blasts. Arms- control advocates, meanwhile, say the US can maintain the stockpile's reliability even without subcritical tests.
A senior administration official defends the SSMP, but adds the US is prepared to withdraw from the CTBT "if the program fails and we can't maintain confidence" in the stockpile. If opponents prevail in blocking Senate approval of the CTBT, it is unlikely that other nuclear powers will ratify it. Experts, however, believe that domestic politics will ultimately compel the Senate to ratify.
Joe Cirincione of the Henry L. Stimson Center, a Washington arms-control think tank, says that given heavy public support for ending nuclear testing, the GOP could be hurt in next year's elections by acceding to conservative opposition to the treaty. "There are some Democrats who relish the idea of the GOP coming out in favor of mushroom clouds in the desert," says Mr. Cirincione.
The administration official touts the treaty's practical aspects, saying that while not fool-proof, it will do much to prevent US foes, such as Iran, from developing nuclear arms. But even if the Senate approves the treaty, it faces another hurdle: It can't go into force unless ratified by all 44 members of the Geneva-based Conference on Disarmament - the club of nations that have nuclear reactors for power or research.
The group includes India, which has refused to sign the CTBT, let alone ratify it. India's rival, Pakistan, says it will only ratify if India does. Both are believed capable of building nuclear bombs. Backers hope world pressure will force the two to ratify.
Asked to rate the prospects for implementation of the Comprehensive Test Ban Treaty, the senior official concedes, "It will be a real challenge."