WASHINGTON -- Four Nobel prize-winning scientists urged President Bush yesterday to take a gigantic leap in arms control by seeking a deal with Moscow to slash U.S.-Soviet nuclear arsenals by 90 to 95 percent.
The combined arsenals, roughly estimated to total about 50,000 warheads, would be cut to no more than 4,000 weapons of all types from so-called tactical or short-range versions to those carried on intercontinental missiles and bombers.
The proposal, in a letter to Mr. Bush, spearheaded a campaign by the Union of Concerned Scientists for radical cuts in U.S. and Soviet weapons and imposition of tough new limits on stockpiles of other nuclear powers.
It was the most far-reaching in an expanding list of proposals for slashing nuclear stocks and tightening controls in the wake of the failed August coup in Moscow.
Nobel laureates signing the letter were Henry W. Kendall, UCS chairman and physics professor at the Massachusetts Institute of Technology; Hans Bethe, Cornell University physics professor and one of the original A-bomb scientists; Glenn T. Seaborg of the Lawrence Berkeley (Calif.) Laboratory and a former head of the old Atomic Energy Commission; and Kenneth C. Wilson, Ohio State University physics professor.
In numerous respects, the UCS's proposals for dealing with "relics of a bygone Cold War" were similar to those recently advanced by the National Academy of Sciences. But the UCS was more specific on the level of cuts to be sought and urged an immediate start with a goal of 2000 as the year for achieving the reductions and new global controls.
"Everybody is getting on the bandwagon for low levels of nuclear weapons," said Jack Mendelsohn of the independent Arms Control Association.
For its part, the ACA has been urging swift action on the 1990 treaty to reduce conventional military forces in Europe, which is languishing in the Senate -- and on the Strategic Arms Reduction Treaty signed in Moscow July 31 but not yet submitted to the Senate.
Arms control advocates are pressing the argument that all weapons-cutting pacts involving Moscow ought to be ratified and implemented before possible further turmoil in the fragmenting Soviet Union.
Jonathan Dean, a former U.S. arms negotiator and one of the authors of yesterday's UCS proposals, said the post-coup situation in Moscow was one of "new opportunities and new dangers."
There were advocates in Moscow for cutting strategic nuclear arsenals to 1,000 warheads on each side, far below the START treaty levels, he said. One of these, Yevgeny Velikhov, a Kremlin arms control adviser, was quoted to that effect in the Washington Post Tuesday.
On the other hand, Mr. Dean and others argue that the attempted coup was not the last likely crisis and that next time control of far-flung Soviet nuclear weapons could break down. "For the first time in 40 years, the opportunity exists to put the nuclear genie largely, if not wholly, back into the bottle," the UCS proposal said.
It said that only the United States could shepherd the global political system through the profound changes required and that nobody short of the president himself could provide the leadership.
There are two chief worries among arms control advocates, both underscored by the four Nobelists in their letter to Mr. Bush:
* The coup attempt made Americans aware that there was a real risk "that political chaos in the Soviet Union might lead to a catastrophic breakdown in Soviet nuclear command and control."
* The "breakup of the Soviet Union" poses a long-term nuclear proliferation threat. Nuclear physicists and facilities throughout the Soviet Union "constitute a potential weapon capability," regardless of current talk of Soviet republics' becoming nuclear-free zones.
The UCS proposed a two-stage reduction program.
From 1992 to 1995, Soviet and U.S. strategic arsenals would be cut to 3,000 to 4,000 weapons on each side -- 60 percent to 70 percent below START treaty limits.
From 1995 to 2000, total stocks would be cut to 1,000 to 2,000 on each side. This would require cutting by other nuclear powers, and a limit of 500 to 700 weapons each should be negotiated for them.