Nuclear weapons are still spreading. So are the sophisticated technologies needed to deliver them rapidly and accurately. Norms against nuclear proliferation continue to erode, creating the impression among would-be nuclear powers that, in some circumstances, proliferation will be tolerated.
These are some of the ominous conclusions of the fourth annual survey of nuclear weapons proliferation, issued by the Carnegie Endowment for International Peace.
According to the newest survey, titled ``The Undeclared Bomb,'' since 1986 Pakistan has become the fourth country to join the club of unannounced nuclear powers.
The survey says the following about this exclusive club:
Pakistan is now believed to have the essentials to rapidly assemble 2 to 4 bombs.
India probably has the materials to quickly assemble 20 to 50 bombs; has greatly expanded its nuclear weapons production capability; and is developing potentially nuclear-capable ballistic missiles (under the auspicies of a civilian space program).
Israel probably has 50 to 100 nuclear weapons and, since 1982, has allegedly built weapons on the hydrogen-bomb principle. It is believed to have deployed a short-range nuclear-capable missile and to have tested an intermediate-range version of the missile in 1987.
South Africa is thought to have been able to build nuclear weapons since 1980-81 and could possibly have an arsenal of 10 to 20 weapons.
These four countries have adopted the strategy of not formally announcing their nuclear capability, but of indirectly sending the message to rivals through ambiguous warnings, says Leonard Spector, author of the Carnegie studies.
Mr. Spector argues that the ``undeclared bomb'' strategy has incurred surprisingly few diplomatic costs for these countries, in part because they are seen as strategically important to the United States and the Soviet Union. But, he adds, the nuclear-weapons potential of the four states could vastly increase the costs of future hostilities in their very tense regions.
Pakistan crossed the nuclear threshold, Spector says, without any sanctions, despite US efforts to block that move and repeated exposure of its clandestine efforts.
Similarly, the Soviet Union transferred a nuclear-powered submarine to India - Pakistan's archrival - and sold it two nuclear power reactors in the last year, despite evidence that India is markedly increasing its nuclear weapons capabilities.
Elsewhere, the US and its allies have not objected to Israel's nuclear program, despite detailed disclosures in late 1986 about the size and sophisticated nature of its nuclear arsenal.
These developments, combined with the use of chemical weapons in the Iran-Iraq war and the spread of ballistic-missile technology, are weakening the norms against proliferation, the study warns. It points to Taiwan's effort to begin plutonium extraction experiments in 1987 (stopped by the US) as a possible example of rekindled nuclear ambitions around the world.
A point of potential progress in this otherwise gloomy survey is Argentina and Brazil. Both countries have mastered the uranium enrichment process and built enrichment facilities. Neither country, however, is believed to be producing weapons-grade material at this time. But during 1987-88, the two countries took a series of confidence-building measures to lessen their nuclear rivalry.
The current cooperation does not, however, provide for verification of the output of either country's enrichment plants. Spector says a high priority for the new US administration and others should be to encourage a monitoring agreement between Argentina and Brazil. This would minimize the chances of a race to get the bomb in Latin America.
The study argues that those trying to halt nuclear weapons proliferation should focus on freezing the nuclear status quo in South Asia and the Middle East. This means, in part, preventing the expansion of existing stockpiles. It also entails delaying or limiting the acquisition of more sophisticated delivery systems, especially missiles.
The spread of chemical arms also needs to be handled, Spector says. Israel, for example, now seems to be projecting its nuclear weapons as a deterrent against potential chemical-missile attack.