Washington — While the debate over defense budget scratching his head over what to do about the MX missile. Mr. Reagan pledged his loyalty to the intercontinental weapon recently. But he also effectively conceded that for all the technical and military advice available to him, a simple and effective means of basing the weapon has not yet been devised.
With the administration agonizing over how to deploy the MX, military analysts are scrutinizing the rationale for developing it. Some claim that its predecessors, the Minuteman II and III, are not as vulnerable as the Pentagon claims -- a conclusion that casts doubt on the need for the MX.
For a variety of political and environmental reasons, Reagan has virtually ruled out the Carter administration's plan to shuttle 200 MX missiles between a network of 4,600 horizontal shelters in Utah and Nevada. Schemes to deploy the MX aboard large aircraft or small submarines also have bitten the dust.
With the elimination of these and other deployment proposals, US Defense Secretary Caspar W. Weinberger now is reportedly poring over a US Air Force plan to shuttle 100 missiles around 1,000 shelters in southeastern Nevada. He also is said to be studying a Rand Corporation proposal to locate 100 missiles among 500 to 600 supertough silos at Nellis Air Force Base in Nevada.
But defense experts point out that the success of any basing system involving deception relies on the Soviet Union's inability to locate the missiles and destroy them. They agree that if satellites, spies, or ground sensors could monitor the numerous clues that reveal the presence of a missile in a shelter or silo -- despite Air Force attempts to mask them -- the MX would be next to worthless.
Rep. David F. Emery (R) of Maine, a member of the House Armed Services Committee, is particularly concerned that Soviet satellite-borne sensors imperil a deceptive basing format, whether it involves shuttling the MX between horizontal shelters or silos.
He contends that the best solution to the MX quandary is to move the 150 Minuteman III missiles at Grand Forks Air Force base in North Dakota to Minuteman II bases and replace the Minuteman III's with MX missiles. The displaced Minuteman IIs would be deactivated, he says. (Minuteman IIs currently are based at Malstrom Air Force Base, Mont.; Ellsworth Air Force Base, S.D.; and Whiteman Air Force Base, Mo.)
Emery also would replace the Air Force's 52 aging titan II missiles with the MX.
To protect the MX deployment at Grand Forks Air Force Base, the Maine congressman favors redeploying the Sprint and Spartan missiles that saw brief service as part of the Safeguard antiballistic missile system at the base in 1975.
Emery is not alone in suggesting this escape from the MX dilemma. Many strategic warfare experts see it as the best way out.
According to one source, there are 400 Minuteman silos that currently can accommodate the MX, which could be housed in silos by 1986 or 1987.
But as the immediate issue of basing is debated, defense analysts are asking a more fundamental question: Is the MX as crucial to national security as both the Carter and Reagan administrations have insisted?
The Pentagon asserts that the MX is needed to replace Minuteman missiles, which it claims are becoming more vulnerable to surprise attack from increasingly accurate Soviet missiles, such as the SS-18 and SS-19.
But skeptical analysts are looking afresh into the question of strategic missile accuracy.
Arthur Metcalf, the military editor of "Strategic Review," claims in the current issue of the journal that "in the present state-of-the-art of missile inertial guidance, targeting accuracies are greatly exaggerated."
Mr. Metcalf, who says billions of dollars could be saved by deploying MX in Titan and Minuteman silos, believes that "neither US Minuteman nor Soviet ICBMs [intercontinental ballistic missiles] are capable of the targeting accuracy necessary to destroy enemy silos."
Last May, William Kincade, the executive director of the Arms Control Association, noted in an article that "no ICBM has even been fired over the North Pole, the shortest route between the US and USSR and the only way our ICBMs can reach them, or theirs us." Scientists and strategists, he went on, "know that the polar magnetic field and other geophysical features or anomalies will affect missile reliability and accuracy in unpredictable ways."
Defense writers Andrew and Alexander Cockburn have observed that ICBMs "do not exist in the orderly universe of the strategic theologians but in the actual world of contract mismanagement, faulty parts, slipshod maintenance, bureaucratic cover-up, and the accidents that have afflicted military equipment since the world's first bow string got wet in the rain."
Richard Garwin, professor of public policy at Harvard University, has observed that in operational conditions US and Soviet missiles not only would be traveling in an untried northerly direction but would be subject to anomalies in the Earth's gravitational field, varying densities of the upper atmosphere, or unknown wind velocities. According to physicist Kosta Tsipis of the Massachusetts Institute of Technology, there are many "sources of error" that can erode missile accuracy.
The Air Force would appear to be aware that its ICBMs lack the accuracy it claims for them. In 1974, then-Secretary of Defense James Schlesinger admitted to a congressional subcommittee that "we can never know what degree of accuracy would be achieved in the real world."
Fred Kaplan, defense policy adviser to Rep. Les Aspin (D) of Wisconsin, expressed his doubts about Minuteman vulnerability in a booklet entitled "A Skeptical Look at the Soviet Nuclear Threat" last year. He claimed that the vulnerability assessment was "divorced from the numerous uncertainties facing any military planner in real life."
Even if the missiles were truly vulnerable, Mr. Kaplan declared, "This fact is not very significant: Land-based missiles constitute only 22 percent of the US strategic arsenal." Thousands of other submarine-launched missiles, cruise missiles, and gravity bombs "could thoroughly blast away the foundations of 20 th-century Soviet society," he asserted.