AMID all the disagreements between the Soviet Union and the United States, there is one issue on which they concur: namely, that no more nations than now possess them should acquire nuclear weapons. The nuclear weapons club is a small one. It is limited to the US, the USSR, Britain, France, and China. India exploded a nuclear device in 1974.
The superpowers signed a nonproliferation treaty in 1968. States with nuclear weapons agreed not to help states without them get them. States without nuclear weapons agreed not to make or acquire them. The right to develop nuclear energy for peaceful purposes was recognized, although this was subject to certain international safeguards and inspection. More than 120 countries ratified the treaty, which set a kind of international code of conduct.
But various key states have not signed it, and recent developments indicate that the elite nuclear club may expand despite the objections of founding members. Two likely new members are Israel and Pakistan.
Israel's capacity to build nuclear weapons has long been considered advanced. Recently Mordechai Vanunu, an Israeli nuclear technician, went public with the story of an Israeli weapons program at a secret nuclear plant at Dimona. Mr. Vanunu, who had apparently worked at the plant for a number of years, told the London Sunday Times that Israel had assembled between 100 and 200 nuclear weapons and provided data and photographs of the nuclear plant.
Vanunu, who left Israel, went to Australia, converted to Christianity, and later traveled to Britain, has disappeared and is believed to be in Israeli hands.
But the story that nuclear weapons are in production in Israel does not startle Western intelligence circles. It lives in a hostile Middle Eastern world, and it fears acquisition of nuclear weaponry by one or other of its Arab neighbors. In 1981 the Israelis destroyed Iraq's Osirak nuclear reactor on grounds it represented a potential threat to Israel.
Much revolves around semantic interpretation of what the ``production'' of nuclear weapons actually means. Some experts think that some countries denying they have ``produced'' nuclear weapons actually have them in place, all but a turn or two of the final screw that would activate them.
South Africa is another country believed in this category. And Pakistan, mindful of neighboring India's nuclear capacity, may also be almost there.
Pakistan's nuclear program has long troubled the US. The Reagan administration has consistently sought, and been given, guarantees that Pakistan is not developing nuclear weapons at its secret Kahuta plant. China's possible involvement in the Pakistani nuclear program has also been a question mark for Washington. Pakistani guarantees notwithstanding, new reports of Pakistani weapons testing have troubled the Reagan administration.
The problem is a difficult one. The US is pledged to halt aid to Pakistan if Pakistan develops nuclear weapons. Yet Pakistan is an American friend, and has stood up sturdily to the Soviets over their occupation of Afghanistan. To cut Pakistan adrift would be hard for the US.
Besides Israel, South Africa, and Pakistan, there are a number of other potential members of the nuclear weapons club. There have been rumors of a North Korean program, which in turn stirs concern in South Korea. Brazil and Argentina are countries with nuclear capacity. Iraq's nuclear program has worried Israel and the capacity of either Iran or Libya to acquire nuclear weapons, if not manufacture them, would be troubling to many.
Thus amid all the talk of nuclear megatonnage and strategic ballistic delivery systems, the superpowers need to keep careful watch on the remote desert nuclear plants where new countries may be developing small, but nonetheless lethal, nuclear weapons.