US lawmakers ask for new arms control initiatives in exchange for backing MX

The political tugging and hauling over arms control and nuclear weapons intensifies this week. And the future of the MX missile is the centerpiece of debate.

President Reagan is stepping up his personal lobbying to win congressional approval of the controversial strategic missile. Key lawmakers, about to decide the fate of the MX, insist on new arms control initiatives as the price of their support.

Sen. Nancy Kassebaum (R) of Kansas, a member of the Senate's Budget and Foreign Relations Committees, told reporters over breakfast Tuesday that it might advance the cause of arms control talks with the Soviet Union if the President were to replace his chief negotiators at Geneva.

Two blocks away at the White House, Mr. Reagan at about the same hour was meeting with his National Security Council to discuss possible changes in the administration's START (strategic arms reduction talks) proposal. Given the lack of progress at Geneva, where talks resume June 8, and the increasing prominence of the arms control issue in domestic politics, such changes seem inevitable. The major decisions now have to do with how much to change the US proposal and when to lay it on the bargaining table.

The President insists that he supports all three major points made recently by the Presidential Commission on Strategic Forces: deployment of 100 MX missiles in existing Minuteman silos, development of a smaller single-warhead missile, and shifting the emphasis in arms control from counting launchers to counting warheads. It is generally agreed that these last two points would increase superpower stability and reduce the likelihood of nuclear war.

But as he indicated in a speech in Ohio this week, Reagan considers deployment of the MX to be his first priority. ''Only when the Soviets are convinced that we mean business will arms control agreements become reality,'' Reagan said.

This puts him at odds with many on Capitol Hill who want greater assurances of the administration's commitment to and flexibility on arms control.

Senate Foreign Relations Committee chairman Charles H. Percy (R) of Illinois said recently that congressional support for the MX ''would be in jeopardy'' unless the administration modified its arms control position. Leading lawmakers in recent days have been more insistent in this regard, and some have been invited to the White House for talks with administration officials.

In general, the current United States position on reducing strategic nuclear weapons and administration plans for strategic modernization are at odds with recommendations of the Commission on Strategic Forces and with a growing number of congressional and other experts.

The commission noted that both the unratified SALT II treaty and START provide ''an incentive to build launchers and missiles as large as possible and to put as many warheads as possible into each missile.''

START would limit the Soviet Union and US to 850 land- and sea-based strategic missiles. (The US currently has about 1,570, the USSR about 2,380.) The Soviets have offered to reduce missile launchers and bombers to 1,800. The administration's proposal also would reduce the number of each side's warheads from about 7,500 to 5,000.

The commissioners lauded this proposed warhead reduction, but said the 850 limit on launchers ''should be reassessed since it is not compatible with a desirable evolution toward small, single-warhead ICBMs.'' They also expressed approval of congressional proposals that would tie any new missile deployment to reductions in deployed warheads.

One such ''build-down'' suggestion, offered by Senate Armed Services Committee members William Cohen (R) of Maine and Sam Nunn (D) of Georgia, would require removing two old warheads from the strategic nuclear arsenal for every new one added.

The Pentagon doesn't favor this approach, and the administration is unlikely to adopt it willingly. Congress may require some form of a build-down as the price for deployment of any MX missiles, however.

Ironically, an increase in launcher limits, together with a lower limit on warheads, may be required to achieve the kind of stability sought by many experts. In essence, this means spreading warheads around so that each launcher is reduced in value and in its potential threat to the other side. This is the idea behind shifting from multiple independently targeted reentry vehicles (''de-MIRVing'') to single-warhead missiles.

Some lawmakers also want the President to establish a permanent bipartisan commission on arms control. Such an advisory panel ''would help establish the kind of bipartisan consensus on arms control that existed during the 1960s,'' said Rep. Vic Fazio (D) of California, 1 of 15 members of the House Appropriations Committee who met with the President recently. ''A commission would also give the Congress and the American people the assurance that this administration is making every effort in Geneva.''