The president has now indicated his willingness to reconsider the Dense Pack basing mode for the MX missile. "There's plenty of room for further discussion," he has said. "If someone comes up with something better, that's fine."

There is something better, but it is not likely that it can be provided so long as the president is determined to stick with the MX missile. In fact, the administration is approaching the matter the wrong way, insisting on the missile while leaving the basing mode dangling. That certainly is not what "closing the window of vulnerability" is all about. While it would be wrong simply to cancel the MX program without having an effective and timely alternative to take its place, Congress would not be wise to change its longstanding insistence that funding for the missile depends first upon an acceptably survivable basing mode.

In addressing the problem, let us return to fundamentals. The fundamental problem is the intolerable vulnerability of our ICBM force. President Reagan emphasized time and again during the presidential campaign, and since, the paramount need to redress this vulnerability and to do so immediately. He said, "Our nuclear deterrent forces must be made survivable as rapidly as possible to close the window of vulnerability before it opens any wider."

What, then, is one to make of the two- year delay in choosing a survivable basing plan for the ICBM force, as well as the choice--apparently still tentative--of a means carrying such uncertainty and risk that three-fourths of the chiefs of staff could not endorse it?

What has been wrong is that there seems to have been some confusion within the administration as to what Reagan and his key defense advisers criticized about the Carter MX plan. It was not the concept of multiple shelter or deceptive basing. Rather, it was, first, that the planned system would not be effective soon enough, and, second, that certain SALT II-directed features made the system too cumbersome, uncertain and costly. As Reagan told the Chicago Council on Foreign Relations in March 1980, the problem with the Carter system is that "we can't complete it until the end of this decade. Given the rapidly growing vulnerability of our land-based missile force, a faster remedy is needed."

The faster, and more effective, remedy, as recommended by the campaign strategic force working group and by the Department of Defense transition team was threefold: re-deploy the existing Minuteman III force in a vertical multiple aim point system in existing deployment areas; proceed without haste with the MX missile and either phase it into the Minuteman MAP system or place it on military land in a lesser deployment than planned; and proceed with high- priority development of a much smaller, single-warhead ICBM.

In fact, with the first and the third elements, the MX would not be necessary. The continuation of the MX program was recommended partly as a concession to the Air Force, and partly as a hedge against unforeseen difficulties with Minuteman redeployment and the small ICBM.

It is true that the MX missile was not criticized during the presidential campaign, and was in fact endorsed by the Republican Party platform. However, none of Reagan's defense advisers, nor the defense transition team, was enthusiastic about the missile. All felt that it was an example of how SALT considerations tend to lead us in the wrong strategic direction. What the Carter administration failed to understand was that a few highly capable missiles can be destabilizing unless very survivably based, but that there is a strong relationship between the size of a missile and the options for survivable basing. The MX is too large and too heavy to be readily adapted to either mobility or concealment; it packs too much capability into too few, highly attractive aim points.

A far better solution would be to distribute the same capability among a larger number of aim points (which is what the Carter MAP plan attempted to do with MX), but to base it on a larger number of much smaller, lighter ICBMs, which could be adapted to a variety of basing modes.

It is ironic that the Reagan administration has rejected the Carter basing plan, which was basically sound in concept, but has accepted the Carter missile, which is basically wrong in concept. It would have been far better to do it the other way around. Since it appears that the political considerations dictated rejection of multiple-shelter basing, because it was associated with the Carter administration, why not reject the Carter missile, too?

Reagan now has an opportunity to have a Reagan missile and a Reagan basing scheme, and have them be a clear improvement over the current direction.

Why not cancel the entire MX program and assign the highest national priority to the development of a small, 25,000-pound single-warhead ICBM and a basing scheme for it? The same strategic capability and number of warheads now planned for the ICBM force, or even more, could be contained in these missiles, which could be deployed in multiple austere vertical shelters in existing ICBM deployment areas or on military land, and/or in a variety of land and air mobile arrangements.

We should be able to develop and produce such a missile without losing time, if we do not proceed with a business-as-usual attitude. After all, when a high national priority was assigned the original Minuteman system, which at the time involved several major technical uncertainties, we were able to go from start of full-scale development to deployment in about four years.

At the same time, it should be possible to take interim measures to relieve part of the existing vulnerability problem by MAP redeployment of at least a portion of the Minuteman III force, by rebasing and increasing alert rates for the B52 force, and by quick fixes to communications.

All in all, these measures would come much closer to closing the window of vulnerability rapidly and firmly than would the MX with Dense Pack or any other likely deployment mode