A top Reagan administration official says it was the Soviets -- not the US -- who insisted 13 years ago that development of exotic defensive weapons should be allowed by the ABM treaty. Despite US opposition, says senior arms control adviser Paul H. Nitze, the Soviet Union insisted that the treaty contain a statement that some Reagan officials now say allows unfettered work on advanced space-based weapons.
Mr. Nitze, who helped negotiate the Antiballistic Missile Treaty in 1972, says the US tried hard to close the door on all new defensive weapons but the Soviets ``would not agree to that.''
In his comments to reporters over breakfast Wednesday, Nitze appeared to provide new justification for a more permissive interpretation of the treaty's provisions governing development of new technologies. Such an interpretation could in itself become a bargaining chip the US could trade for Soviet concessions at the Geneva arms talks or the November summit.
But Nitze's comments leave unanswered the more central policy question of whether the US would actually forgo an arms deal with the Soviets by insisting on the right to test. Last month, the Soviets proposed a 50 percent cut in the size of US and Soviet strategic nuclear arsenals in return for curbs on the development of the space-based Strategic Defense Initiative (SDI).
Disagreements over the correct interpretation of the ABM treaty first surfaced two weeks ago when national security adviser Robert C. McFarlane told reporters that the US was allowed to go beyond research to actual testing of new space-based defenses.
In a series of mixed signals that followed, Mr. McFarlane's loose interpretation was corroborated by the Reagan administration's leading hawk, Assistant Defense Secretary Richard C. Perle, then narrowed by Secretary of State George P. Shultz.
In an apparent effort to allay Western European fears that next month's superpower summit could break down over the SDI issue, Mr. Shultz said the US would strictly honor the ABM treaty, implying that SDI would be limited to research.
Arms control advocates, led by former US Ambassador Gerard Smith, who was the chief negotiator of the ABM treaty, insist that the pact imposes strict limits on testing and development of SDI.
Disagreements within the US over interpretations of the ABM treaty take place as both sides scramble for the moral high ground on arms control. On Tuesday, Defense Secretary Caspar W. Weinberger announced that the Soviets have deployed a new, mobile, single-warhead missile -- the SS-25 -- in violation of the provisions of the unratified 1979 SALT II agreement.
That treaty limits both superpowers to the development of one ``new type'' of missile. US officials say the Soviets have already begun testing one new missile, the SS-24. Weinberger said by developing a second new missile, the Soviets have underscored the fragility of arms control agreements covering offensive weapons and the need for new missile defenses such as those envisioned under the SDI program. The Soviets, for their part, reply that the new SS-25 is simply a modification of an existing missile,
the SS-13. Such modification is allowed under the SALT II accord.
Soviet officials also warned Tuesday that US efforts to develop a space-based missile defense would undermine any basis for an arms agreement in Geneva. Speaking in Moscow, Sergei F. Akhromeyev, chief of the Soviet General Staff, warned that the Soviets would match US efforts at whatever cost.
On the subject of Soviet arms cut offers, the silver-haired Nitze, one of the most experienced of US arms control experts, said the US has to ``separate the nuggets from the mass they're buried in.''
One nugget in the USSR offer to reduce nuclear bombs and warheads by 50 percent, say other administration officials, is the Soviets' apparent willingness to cut their arsenal of heavy land-based missiles. These accurate, powerful missiles threaten US land-based nuclear forces and may be the Soviets' most fearsome weapon.
Less advantageous to the US is that the Soviets have shaped their offer in a way that would bolster their superiority in theater nuclear weapons in Europe.
The effect of the Soviets' definitions is to include US forward based systems [such as aircraft on carriers] and exclude all Soviet nuclear systems which threaten US allies. ``Clearly our forward based systems are where they are in order to help defend our allies,'' says Nitze.