US grapples with ABM definitions. White House hedges on earlier view of missile-defense treaty

The Reagan administration has gingerly walked back from a new and controversial United States interpretation of the ABM treaty. But it has not wholly dispelled concern about the issue in Congress, among Western allies, and in the arms control community.

Two fundamental issues still need clarification:

Does President Reagan reserve the right to interpret the 1972 Anti-Ballistic Missile Treaty as permitting the testing and development of exotic space-based technologies under his ``star wars'' program?

Does such a legal reinterpretation of the treaty conform to the legislative record -- or does it overturn the Senate's interpretation of the treaty 13 years ago, thereby raising a constitutional question?

As the House Foreign Affairs Committee prepares for hearings on the ABM treaty next week, there continue to be differences of opinion even within the administration. Hard-liners who do not want the President's Strategic Defense Initiative (SDI) to be bargained away at the coming summit meeting strongly back a new legal interpretation of the treaty.

``In my judgment there is one correct view of what the treaty provides,'' Assistant Secretary of Defense Richard N. Perle told reporters yesterday. ``After one wades through all of the ambiguities and reads carefully the text of the treaty itself and the negotiating record . . . with respect to systems based on `other physical principles' [such as lasers and directed-energy weapons], we have the legal right under the treaty to conduct research and development and testing unlimited by the terms of the tre aty. . . .''

Secretary of State George P. Shultz has sought to calm the furor here and abroad over this new interpretation, which originated in Mr. Perle's office and was floated publicly by national-security adviser Robert C. McFarlane. Mr. Shultz announced recently that the US will continue to limit testing and development of weapons under the SDI program according to a ``restrictive interpretation'' of the accord. SDI will be pursued ``as currently structured,'' he said.

But Mr. Shultz did not repudiate the new legal interpretation, which drew sharp criticism from lawmakers in Congress and immediate protests to the White House from London and Bonn. Uncertainty therefore persists about the President's future course.

Some arms control experts credit Mr. Shultz with buying some time while the issue is sorted out beforethe summit meeting, where the ABM Treaty will figure heavily in the arms control discussions.

The essential elements of the issue are these:

Article V of the treaty prohibits the development, testing, or deployment of ABM systems or components that are space-based, sea-based, air-based, or mobile land-based. In the view of arms control advocates, this is a clear ban on the development or testing of SDI components. It does not rule out research on SDI, however.

But according to the McFarlane-Perle interpretation, testing and development of exotic space-based weapons is permitted under Agreed Statement D, which is appended to the treaty. This states that if new ABM systems ``based on other physical principles'' are created, limitations on them would be subject to further discussion and agreement between the US and Soviet Union.

Those who negotiated the treaty say that Agreed Statement D was meant to supplement Article III of the treaty, which permits the deployment of a limited number of fixed, land-based ABM missiles, launchers, and radars based on then-current technologies. Hence, Agreed Statement D is viewed as having application only to fixed, land-based ABM systems using exotic technologies -- and not space-based systems.

But Perle suggests that Agreed Statement D was signed by the two sides to take account of the Soviet position that the ABM treaty should not rule out testing and development of future technologies. The statement does not relate to Article III, he says, and in fact overrides the restrictions in Article V.

Many arms specialists say the legislative record supports the interpretation given the treaty by previous administrations. Alton Frye, an arms expert at the Council on Foreign Relations, recalls that, when the treaty was debated in the Senate Armed Services Committee in 1972, the late Sen. Henry M. Jackson berated military witnesses for having accepted limitations on the testing and development of new technologies. And he voted for the pact with the understanding that Article V precluded the developme nt and testing of such technologies as lasers except in fixed, land-based ABM systems.

Only two senators voted against the pact, says Mr. Frye. One of them, James L. Buckley, did so on grounds that the treaty banned the testing and deployment of lasers based in space.

``The Senate was absolutely clear beyond any doubt that this was the interpretation on which it based its ratification,'' says Mr. Frye. ``So I see deep constitutional problems, a usurpation by the executive of the congressional role.''

The President, said Perle, has found that the pact was incorrectly interpreted in the past but that he draws a distinction between broad interpretation of the treaty as a matter of law and present SDI activities that are based on a narrow interpretation. ``If and when the issue arises of activity that would be permitted under one interpretation but not under the other, then that activity would be weighed with the knowledge that we have a full legal right to act based on what we now hold to be the corr ect interpretation of the treaty,'' said Perle.