Pentagon leaders, after reviewing the options for President Carter, have concluded that the United States should add some kind of mobile land missile to its strategic arsenal.
Settling for more submarine missiles, rather than trying to make landbased missiles harder to hit by moving them around on the ground or taking them aloft in ariplanes, has no high-level support in the Pentagon, defense officials said yesterday.
Defense Secretary Harold Brown, they added, will detail the Pentagon case in a meeting with Carter soon. The Brown-Carter meeting could be between now and Monday, they said, or be delayed until May 21 when Brown is scheduled to return from a trip to Europe, depending on the president's schedule.
The thrust of the Pentagon argument is that some kind of mobile land missile will preserve that leg of the triad-consisting of land missiles, submarine missiles and bombers-by making it less vulnerable to increasingly accurate Soviet warheads.
Pentagon weapons specialists who just finished studying the options for deploying the new missile, called MX, have rejected the contention that it would be a losing proposition to make the MX mobile. Currently the United States had 1,054 strategic missiles underground in silos. None is mobile.
To make the next generation land missile harder to hit, the Pentagon looks favorably upon hiding 200 of them among 4,000 identical holes in the ground-moving each missile from hole to hole covertly.
A second option with Pentagon support would put some of the new MX blockbuster missiles in airplanes at the first warning of attack so the missiles could escape destruction on the ground from a Soviet first strike.
Critics contend that the Soviets, in response to the shell game concept of moving 200 missiles among 4,000 holes, would build more warheads to cover all the holes. Also, thes critics contend, the Soviets might well resort to the same type deployment-causing the United States to build more warheads as well, heating up the arms race.
The option of making the MX airmobile, according to its opponents, would be too expensive-about $30 billion by the Air Force's estimates. Under some new Pentagon arithmetic, that estimate has been lowered on the theory that any planes built to carry the MX aloft could also be used for cruise missiles.
Brown went over the MX options with Carter's defense advisers at the White House on Friday, but no decision was made on any of them. The shell game concept and the air mobile MX were two of five options explored. The three other options are these:
Split the new force of MX missiles between planes and existing Minuteman silos; install