Foreign Relations of the United States, 1989–1992, Volume XXXI, START I, 1989–1991

80. Memorandum From Senator Nunn to President Bush¹

Washington, February 22, 1990

SUBJECT

• Ban on Mobile MIRVed ICBMs

I have been urging the Administration to propose a ban in START on mobile MIRVed ICBMs because I think it makes sense in terms of greater strategic stability and because I think it may be your only hope for maintaining congressional support for the Rail Garrison MX and the Midgetman programs this year.

I do not see a ban on mobile MIRVed ICBMs as an end in itself and would not advocate it if it were. Rather, I see it as a halfway step toward an ultimate goal in START II of banning all MIRVed ICBMs, including those in silos. It is too late in the START I negotiations to try to ban all MIRVed ICBMs, but a window of opportunity is still open to ban mobile MIRVed ICBMs.

Some have suggested that we wait until START II to seek a ban on mobile MIRVs, rather than negotiate it now. Setting this as a goal for START II is better than never proposing it in terms of our long-term objectives for greater strategic stability. However, I do not think that will save the “two-missile” program on the Hill this year since Members will not be attracted to the idea of spending another $4.9 billion to complete the program before it could be traded away in arms control.

The hard reality, Mr. President, is that absent a mobile MIRVed ban in START, the votes are not there this year for the two ICBMs. I believe if one missile is defeated, both will probably fall in a kind of “mutual fratricide” sequence. I supported the “two-missile” package last year because I thought I had implicit assurances the United States was going to propose a mobile MIRVed ban, but I cannot support the package this year absent this change.

I am, of course, not alone in advocating a ban on mobile MIRVed ICBMs. The idea is widely supported on the Hill and has been endorsed by three former JCS Chairmen, Harold Brown, Bud McFarlane, Jim Woolsey, and Brent Scowcroft, among others. I have attached a paper containing representative statements in support of this proposal, as well as quotations by some who do not favor it.

Secretary Cheney has strongly opposed the idea. His main objection seems to be that since Midgetman will not be available until 1997, the Soviets would have a mobile ICBM (the single-warhead SS–25) and we would have none for a number of years if the Rail Garrison MX is traded for the SS–24. There are two problems with that argument. First, we have been living with, and will continue to do so for a few more years, a situation where the Soviets have two mobile ICBMs (the SS–25 and SS–24) and we have none, yet no one is suggesting that our deterrent has been undermined. Second, the reason the Midgetman will not be ready until the late 1990’s is because the Administration decided to deploy the Rail Garrison MX first. We could probably move up the Midgetman timetable up by a year or so if we increased the funding for Fiscal Years 1991 and 1992.

Secretary Baker has not supported the idea either, apparently because he is worried that it might delay START. However, the two most influential military arms control advisors in the Soviet Union, Marshal Akhromeyev and General Chervov, have made public statements indicating that the Soviets might be receptive to the proposal. START will not be delayed if the Soviets see the proposal as being in our mutual interest.

Some Air Force leaders have argued that leaving the MX in silos will make them more vulnerable. But unless the United States receives and acts on strategic warning, the missiles will be far more vulnerable sitting in their garrisons in frail boxcars than they are now in their hardened shelters. And as each side begins to acquire near real-time capabilities to detect, track and target mobile ICBMs (a capability General Chain recently touted in a press interview), the advantages of rail-basing will dissipate, even if we did disperse the trains on strategic warning. The main point, though, is that banning the mobile MIRVs is just a stage on the road to a genuinely more stable strategic balance in which all land-based MIRVs are banned.

I think the strategic arguments for this idea are sound. But the issue cannot be debated in a political vacuum. With a U.S. proposal to ban mobile MIRVs, a majority in Congress might be willing, albeit reluctantly so, to go along with RGMX. With the proposal, I can argue that in voting funds for MX, they support a negotiating position that will lead to elimination of the rebasing of MX and destruction of the Soviets’ SS–24 rail mobile ICBM systems. In addition, some who are currently opposed to Midgetman may reluctantly support that program if they think there is a serious prospect that START will ban RGMX, thereby making Midgetman our only option for achieving mobility in the ICBM force.

Let me add one other dimension. We have to start looking ahead to the START ratification hearings. The intelligence community has cautioned that Soviet rail-based ICBMs present especially difficult verification problems and that it would be harder to verify Soviet compliance with a numerical ceiling on rail-based ICBMs than a numerical limit on truck-mounted ICBMs.

In addition, a ban on mobile MIRVed ICBMs would aid START ratification by eliminating a particularly worrisome breakout scenario. If the Soviets are not permitted a legal SS–24 force under START, along with its whole deployment infrastructure, then there would be no training, logistics, or deployment base for the Soviets to exploit were they to try to hide a large force of illegal SS–24 trains. In this case, the Soviets would not likely take the risk of cheating. To be sure, the Soviets could covertly hide SS–25s, but would they take this chance if every illegal SS–25 got them only one additional warhead (versus 10 RVs for each hidden SS–24)? Those who raised this argument with regard to the secretly hidden SS–20 scenario during the INF ratification debate did not get very far.

For all these reasons, I urge you to consider this proposal.

Quotes on Mobile MIRVed Ban Proposal

1. Brent Scowcroft, Nick Brady, Harold Brown, Lloyd Cutler, John Deutch, Al Haig, Richard Helms, Henry Kissinger, Mel Laird, Bill Perry, Don Rumsfeld, Jim Schlesinger, and Jim Woolsey (members of and counselors to the Scowcroft Commission), December 9, 1987:

The rail-garrison basing for the MX missile, while possessing attractive features, is not a substitute for the Small Mobile ICBM, inasmuch as it requires significant warning time to achieve survivability.

2. Harold Brown, Les Aspin, Bill Cohen, Joe Jordan, Bud McFarlane, Sam Nunn, John Warner, and Jim Woolsey (CSIS “Discussion Group on Strategic Policy”), January 1989:

We should . . . give consideration to proposing a continued ban on multiple independently targetable reentry vehicle (MIRVed) mobile systems in view of their more accelerated effects in cheating scenarios. A trade of the MX for the SS–24 deserves serious consideration.

3. Admiral William Crowe (former JCS Chairman), February 2, 1990:

That [banning mobile MIRVed ICBMs] absolutely makes eminently good sense . . . I would buy it in a heartbeat.

4. General David Jones (former JCS Chairman), February 2, 1990:

I would try, for example, the rail mobile MX and the SS–24. I think it was a good idea to try to trade that off.

5. General John Vessey (former JCS Chairman), February 2, 1990:

I would sure try to get rid of MIRVed mobiles in the negotiating side of the house, and not have to deploy the rail mobile MX.

6. Harold Brown, February 6, 1990:

I think that would be a very good trade.

7. Senator Wallop, February 6, 1990:

It would be a good trade-off.

8. Soviet Marshal Akhromeyev, July 28, 1989:

If there appeared any specific proposals on this particular issue, then the Soviet Union will [consider them] with the greatest care and attention. I consider this to be a serious kind of proposal and I now confirm this here today.

9. Soviet General Chervov, January 21, 1990:

I believe it is possible [to ban mobile MIRVed ICBMs]. [Both sides] would win by eliminating a great number of MIRVed missiles, provided that no additional such missiles are created.

10. Richard Perle, January 24, 1990:

For the foreseeable future, I believe we can safely reduce the investment we make in protecting against a massive surprise Soviet nuclear attack . . . I would not proceed with either the Midgetman or the rail mobile MX.

11. General Chain, February 17, 1990:

[I am] strongly opposed. I don’t think the Soviets would have one hiccup with us having the rail-garrison Peacekeeper.

12. Secretary Cheney, February 1, 1990:

In terms of the notion of a trade-off between the SS–24 and the Peacekeeper, I would have problems with that, primarily because I do not think you want to get into a position where the final result is the Soviets have mobile missiles and we do not and because at this time the Peacekeeper is our only system that is likely to be operational any time in the near future. The Small ICBM comes into the force in the last nineties. We would end up—if you were to cut that kind of deal—where the Soviets would give up their SS–24 on rail and presumably they would keep those in silos and we would keep ours in silos, and the Soviets would have several hundred SS–25s.

1. Source: Department of State, Economic and Agricultural Affairs, Lot 96D484, Robert B. Zoellick, Under Secretary for Economic and Agricultural Affairs, Gates Group NODIS. No classification marking. Eyes Only. Brackets are in the original. Printed from an uninitialed copy.