Without a bipartisan political consensus on nuclear arms and arms control, it is unlikely that the controversial MX missile will ever be built, Brent Scowcroft warned this week. It's equally unlikely the United States and the Soviet Union will reach an accommodation on strategic weapons, he said.
Mr. Scowcroft, who heads the presidential commission on strategic forces and is a key figure in the Washington arms control debate, will be taking a more visibly active role in coming weeks. Acting as a liaison between the administration and Congress, his group will suggest ways to accelerate what until now has been a relatively slow pace in strategic arms negotiations at Geneva.
''If all hands in the government put their minds to it, it is conceivable that substantial progress can be made,'' Scowcroft told reporters at the Pentagon Thursday.
While the MX has survived years of criticism, congressional approval of the large intercontinental ballistic missile (ICBM) has never been more than half-hearted and tentative. Just as the missile is seen by the administration as a lever to pry the Soviets away from their reliance on very large land-based rockets, so is it viewed by many supporters on Capitol Hill as a bargaining chip to urge the White House toward greater efforts at Geneva.
Before they left town last month, House and Senate budget conferees approved production of the first 21 MX missiles, six fewer than the administration had wanted for the coming fiscal year. Pro-MX Democrats, led by Rep. Les Aspin of Wisconsin, also won approval of an authorization amendment linking MX production to design, development, and testing of the smaller, single-warhead missile dubbed ''Midgetman.''
Representative Aspin has been one of many participants and observers noting the need for a clearer domestic political consensus on strategic arms and arms control before headway can be made at Geneva.
The first indication of the possibility of consensus came last spring with the recommendations of the Scowcroft Commission. In essence, the panel of experts, appointed to find a basing mode for the MX, repudiated President Reagan's persistent warnings about the so-called ''window of vulnerability,'' the period of time during which the Soviets supposedly would be able to threaten US land-based strategic forces before new ones could be deployed.
The commission said that such concerns about US ICBM vulnerability had been overstated in light of the deterrent effect of overall American strategic forces.
But it did outline certain steps that could increase superpower stability and lessen the likelihood of nuclear war. These included: deploying 100 of the 10 -warheaded MX in existing Minuteman missile silos; developing a smaller, single-warhead missile that could be mobile; and shifting emphasis in arms control goals from launchers to warheads.
Scowcroft, a retired Air Force lieutenant general and national security adviser to former President Ford, is a highlyrespected figure in Washington, and it was his low-key approach and seemingly reasonable recommendations that convinced key moderate Republicans and liberal Democrats to approve initial MX production. But many of these important lawmakers are short on patience with the White House in regards to arms control.
''Arms control was one of the three legs of the commission's proposal last spring,'' Aspin wrote Mr. Scowcroft this week. ''It is obviously the weakest leg and needs attention if the Scowcroft package is to be a reality.''
While there has been no breakthrough on reducing strategic weapons, movement on both sides has been evident.
The US has eased its stance on sharply reducing the large number of heavy, multi-warheaded Soviet ICBMs. The Soviet Union also has dropped some of its demands and apparently is developing a relatively small, single-warhead missile. Shifting to such missiles on both sides, many experts feel, would make superpower strategic forces less threatening, less vulnerable, and thereby increase stability.