Foreign Relations of the United States, 1981–1988, Volume XLIV, Part 1, National Security Policy, 1985–1988

238. Memorandum From Secretary of Defense Weinberger to the President’s Assistant for National Security Affairs (Powell)¹

Washington, November 23, 1987

SUBJECT

• Requirement for a Legal Opinion on the Place of Kinetic Energy Systems in the ABM Treaty (S)

(S) After months of ABM Treaty review there is one central issue that remains to be resolved: Are space-based kinetic energy systems based on “other physical principles” and governed by Agreed Statement D, or are these systems conventional ABM systems governed by the body of the ABM Treaty? This is a critical question, because, if kinetic energy devices are not based on “other physical principles,” testing and development of these devices in space would be prohibited under both interpretations of the ABM Treaty.

(S) As you are aware, space-based kinetic interceptors are key to the effectiveness of the first and second phases of the strategic defenses currently envisioned. Additional restrictions on our ability to conduct development and testing in these particular technologies would have the most deleterious consequences for the strategic defense program and for our effort to move the Soviet Union towards reductions in offensive forces. Since we may arrive at an understanding with Congress which would permit us to plan for space-based experiments under the broad interpretation, it is imperative that our obligations under the ABM Treaty with respect to kinetic systems be clarified without delay.

(S) While there is no doubt in my mind that these advanced systems are indeed “exotic” and that their development and testing is not restricted by the Treaty which we signed in 1972, I believe the President would be best served by a formal opinion to this effect. The President should know where we stand on this issue by mid-November and certainly before he meets with General Secretary Gorbachev. Thus, I urge that you ask Judge Sofaer to provide such an opinion as soon as possible.

Cap

1. Source: Reagan Library, William Tobey Files, Subject File, Gorbachev and SDI. Secret. Weinberger wrote “Colin” above the recipient line. On November 5, Reagan announced that Powell would succeed Carlucci as the President’s Assistant for National Security Affairs, and that Carlucci would succeed Weinberger as Secretary of Defense on November 23.