Washington — President Reagan's decision to base a number of MX missiles in fixed silos long targeted by the Soviet Union rather than shuttle them around a system of protective shelters followed a Defense Department admission last week that the Kremlin's SS-18 missile has a "high probability" of being able to destroy "any known fixed target."
President Reagan's abandonment of the "shell game" basing method for the MX, which came three days after the Defense Department emphasized the size, destructiveness, and accuracy of the SS-18 in a booklet entitled "Soviet Military Power," has left many congressmen and defense analysts gasping in disbelief.
They point out that the silos currently housing the nation's force of 52 Titan II and 1,000 Minuteman II and III intercontinental ballistic missiles are rapidly becoming vulnerable to the increased quantity and accuracy of warheads that Soviet missiles can deliver. Deploying MX in the sort of multiple protective shelter (MPS) system that the Carter administration favored would have accorded the missile a higher degree of survivability, they argue.
Sen. John Tower (R) of Texas, chairman of the Senate Armed Services committee , clearly was angered by Mr. Reagan's decision, claiming it "leaves us with a highly vulnerable land-based system."
Among military experts, only those skeptical of the Soviet Union's ability to destroy Titan and Minuteman in their silos, such as Paul Warnke, the former director of the Arms Control and Disarmament agency, seem pleased with the President's announcement.
Unveiling last week a $180.3 billion plan to revitalize US strategic forces, Reagan claimed that MPS basing for the MX "would be just as vulnerable as the existing Minuteman silos" because "no matter how many shelters we might build, the Soviets can build more missiles, more quickly and just as cheaply."
Meanwhile, other basing modes will be studied and a choice made by 1984, the President said.
According to defense officials, 36 MX missiles will be installed in Titan II silos by 1986. Currently deployed in Arizona, Kansas, and Arkansas, the accident-prone Titan II is to be deactivated.
The sudden switch from an MPS to basing the MX in silos is something of an embarrassment for Defense Secretary Caspar W. Weinberger, assert some analysts. They point out that during his confirmation hearings, he declared silos to be vulnerable because they are known and incapable of reinforcement. Answering such criticism on CBS's "Face the Nation" Sunday, Weinberger laid great stress on "superhardening" the silos, which, he said, will provide "much greater survivability for a few years."
"Superhardening," observed Senator Tower on NBC's "Meet the Press" Sunday, "doesn't buy more than a little time." He added that increasingly accurate Soviet missiles will even be able to destroy silos thus reinforced.
How the Joint Chiefs of Staff regard the President's MX decision is unclear. After the announcement last Friday, Weinberger said they endorsed "pieces" of his strategic plan, which also calls for the construction of 100 B-1 type bombers. But he said he would make "no predictions" about their reaction, observing merely "I have hopes."
While the MX rolls off production lines and into silos over the next few years, the Defense Department will study three ways of deploying it more survivably: by basing it deep underground; by sending it aloft on long-endurance aircraft; and by providing it with ballistic missile defenses (BMD).
Deep underground basing would provide excellent survivability but the devastation wreaked by a nuclear blast on the surface could leave a missile trapped uselessly in its silo, say experts. Moreover, its depth might pose maintenance problems.
Putting the MX aboard continuously patrolling aircraft appears flawed. Last year William J. Perry, then undersecretary of defense for research and engineering, said the Soviets could "barrage attack the air space over the central US" and with 'a few thousand warheads . . . could . . . destroy every airplane in about half a million square miles."
Ballistic missile defense (BMD), moreover, is far from foolproof. "What we have now," said the secretary Oct. 2 referring to the low altitude air defense system (LoADS) "is not good enough." He said that it only "works on 50 percent of missiles" and "thus far does not offer a high degree of protection.
Weinberger made it clear that the Pentagon may not select only one basing mode for the MX in 1984. The missile could be deployed in all three ways he said. But if none are found to offer the MX better survivability, he observed, the missile could stay in its silos.
The administration insists that the MX decision is but one aspect of a large, mutually reinforcing strategic arms package designed to half the decline in US military strenght.
The President's plan, besides fielding 100 derivatives of the B-1 bomber, calls for "vigorous" development of a radarbaffling "Stealth" bomber. More than 3,000 cruise missiles will be deployed on B-1s, B-52Gs, and B-52Hs.
At sea, a larger, more accurate ballistic missile called the D-5 will be deployed on Trident submarines and several hundred nuclear-tipped, sea-launched cruise missiles will be assigned to general purpose submarines.
The North American Aerospace Defense Command is to get improved radars, airborne warning and control system (AWACS) aircraft, and F-15 fighters to replace its aging F-106 interceptors. In addition, the survivability and endurance of much neglected strategic communications and control systems will be improved significantly.