Several countries on or near the threshold of the world nuclear-weapons club are carefully watching a pending United States decision on sales of nuclear fuel to India.
One of them is India's neighbor and rival, Pakistan, which US experts say is moving steadily closer to a probable test of its own nuclear bomb.
A recent $1.8 billion Soviet conventional arms sale and reports of Soviet deliveries of heavy water, a key nuclear element, to India, have reinforced Pakistani President Zia ul-Haq's determination to push ahead with the Pakistani program, these experts add.
Other aspiring or actual nuclear states are waiting to see whether President Carter overrides the US Nuclear Regulatory Commission (NRC) decision of May 16 to reject India's purchase of 38 tons of enriched uranium for its Tarapur nuclear power plant.
Several members of Congress, including Sen. Alan Cranston (D) of California and Rep. Edward Markey (D) of Massachusetts, support denial to India of enriched uranium from the US. India, they recall, exploded a nuclear device in 1974 and still refuses to accept full international safeguards on its nuclear power facilities.
Representative Markey, in the June 9 Washington Post, singled out "Argentina, Brazil, Egypt, Israel, Spain, Taiwan, and Turkey" as threshold countries to which "the same strict standards should then be applied if they continue to refuse a pledge of no nuclear explosives."
These lawmakers and some administration analysts believe President Carter's desire not to antagonize the government in New Delhi in the wake of the Soviet invasion of nearby Afghanistan is the main reason for his support of the fuel shipment to India.
"There's more to it than that," argues one expert high in the administration who favors the sale. "If we deny India the fuel, Prime Minister Indira Gandhi's government is likely to pull out of its nuclear cooperation agreement with the US. We would then lose whatever leverage or talking power we still have to dissuade the Indians from further weapons development, or from moving closer to the Soviets."
If President Carter does override the NRC's "no" to India, Congress could still halt the shipment, if both Houses disapproved within 60 days of the President's order.
Both Canada and the US had contributed technology India used in its 1974 test explosion. While Canada cut off all nuclear help after the test, the US continued selling enriched, weapons-grade uranium, reactor parts, and various nuclear services.
The American hope was that the continued relationship would give the US leverage, under the nuclear nonproliferation policies President Carter proclaimed when he took office in 1977 and wrote into the Nuclear Nonproliferation Act of 1978, to keep the Indian program a peaceful one.
However, although former Indian Prime Minister Morarji Desai termed the 1974 explosion a "mistake," India still refused to sign the 1968 Nuclear Nonproliferation Treaty (NPT), which comes up for review at a conference due to open in Geneva Aug. 15.
India also stated it reserved its right to continue nuclear experiments, as well as manufacture of plutonium. Its use of about 200 tns of US-supplied enriched uranium at Tarapur has reporetedly yeilded 1,500 tons of plutonium as a byproduct of its two 200-megawatt reactors. This is enoguh plutonium to manufacture many nuclear bombs.
In Vienna March 2, Munir Ahmad Khan, chairman of Paskistan's Atomic Energy Commission, rejected the official Us thesis that reprocessing and enrichment of uranium and fast breeder reactor technology should be confined to original members of the "nuclear club" -- the US, the USSR, Britain, France, and China.
President Zia said March 11 that Pakistan would continue its nuclear program. It was Pakistan's "basic right" to use nuclear technology to solve its energy problems and make economic progress, he said.
US analysts say France's 1978 refusal, on US urging, to supply Pakistan with a reprocessing plant to produce plutonium merely caused Pakistan to switch its strategy and try to catch up with India by building a plant to enrich uranium to weapons grade. They now estimate Pakistan may be ready for a test explosion within six months to a year.