The President's proposal to deploy 100 MX missiles in Minuteman silos will never come to pass. This became clear on June 14 when 48 senators voted for an amendment Sen. Lawton Chiles (D) of Florida and I proposed to prohibit deployment. This was, by five, the greatest number of votes gathered against the President's MX proposal. We lost that day; the Senate deadlocked 48-48, and Vice-President George Bush cast the deciding ballot in favor of the program. One absent senator had voted with us before; another announced he would, for the first time, vote against the MX.
The next Senate vote on this could well mark the end of the program.
Our argument against the administration's MX deployment scheme is that it would undermine the doctrine of deterrence, which has for more than a generation served to keep the nuclear peace.
From the time Americans learned the Soviets had developed the capacity to deliver a nuclear bomb to the US, that policy of deterrence has guided both our thinking about how to build nuclear weapons and our planning as to how to avoid nuclear war. It has been followed with great faithfulness by every president since Eisenhower. Until now.
At the heart of deterrence theory is the proposition that war is deterred by making it clear that war cannot succeed. We seek to deploy our nuclear weapons in ways that make them invulnerable to a first strike, so the US is in a position always to strike back in force if attacked.
It happens I was a member of the Cabinet 15 years ago when that distinguished secretary of defense, Melvin Laird, began regularly to inform us that the Soviets were developing large land-based missiles with a degree of range and accuracy such that our Minuteman missiles, not originally vulnerable to a first strike, were becoming very much so.
If this continued, Laird said, we would have to get out of those silos if our land-based missiles were to continue to be deployed in a deterrent mode. In time , it was decided - reluctantly, and with no great rush to judgment - that a new missile would have to be developed and deployed elsewhere in a comparably invulnerable mode.
What emerged was the M (for missile) X (for experimental). Because the Strategic Arms Limitation Treaties (SALT) limited the number of missiles the US and Soviets could have, it was thought necessary to pack as much power as possible into them. With 10 warheads, each with almost 10 times the power of the warhead that destroyed Hiroshima, MX became very powerful indeed; also a very valuable target.
Having so designed the missile, we set out to find a way to deploy it. For a decade the MX wandered in the desert, searching for an invulnerable basing mode. Thirty-two basing plans were considered, but each was found unacceptable.
To overcome this seemingly insuperable problem, President Reagan appointed a commission, chaired by Gen. Brent Scowcroft, a man of unquestioned integrity and knowledge in this field. In April 1983 the commission proposed we move as rapidly as possible to deploy a mobile single-warhead intercontinental ballistic missile (ICBM) of approximately 15 tons. This ICBM is called Midgetman, and its explicit purpose is to maintain our deterrent posture. Unfortunately, the report also suggested we build and deploy the MX missile in the very Minuteman silos whose vulnerability had forced the search for a new missile.
Let us be clear about what this means. The MX in Minuteman silos can be instantly destroyed by a Soviet first strike. Which means that in a crisis, the Soviets must think our only choice is to ''use 'em or lose 'em.'' This knowledge allows them 10 minutes to preempt it. The moment those missiles are deployed, the world goes on a 10-minute trigger, called ''launch on warning.''
The world also loses one of the pillars of what is known as crisis stability. In situations of international tension - most recently in Lebanon - Soviet leaders have known what to expect from us. We will not begin a nuclear exchange. It is their choice whether to commence one. They know our doctrine is to respond. Have they ever had to ask themselves: Is the US thinking we are about to start something? Do the Americans feel they had better launch their Minuteman missiles? Does Soviet security require a preemptive launch on warning? One easy answer to all questions: No. But put the MX in those Minuteman silos and all the answers become: Yes.
The amendment Senator Chiles and I offered would not have allowed us to put ourselves on that 10-minute hair trigger. Instead, it would have refocused our strategic modernization in a stability-enhancing direction.
The MX does not do this; Midgetman does. It has the virtues of a deterrent weapon; it is widely dispersible; it can be mobile. It would get us out of the holes that represent the basic tactical vulernability of fixed ICBMs.
Perhaps, if we choose this course, the Soviets in time may also judge that there is greater strategic security to be got out of mobile, small, single warhead missiles. Half the US Senate evidently agrees. Half plus one could restore to American policy a commitment to deterrence.