Finally, after nearly two years of pondering the political complications of various basing modes -- from the rip-up-the-wild-West "race-track" plan, to dropping them from planes, to trucking them around on our interstate highway system -- the Reagan administration is submitting plans to Congress for deploying the MX missiles. Yet, for all the deliberation, this program -- which promises to soak up tens of billions of scarce defense dollars -- still will not meet even its basic objective of survivability. Ultimately, it may even threaten the steady consensus that has been building in Congress for a strong yet reasoned defense policy.

The Reagan "Dense Pack" proposal is supposed to bury 100 MX missiles in closely spaced "super- hardened" shelters that will be four times more blast resistant than current U.S. Minuteman silos. But even the defense secretary's own experts have criticized such a scheme. Dr. Charles H. Townes, who headed up Weinberger's MX advisory team, doubts that any silo can be hardened to the degree necessary to make Dense Pack viable. And the Air Force, sensitive to the criticisms of the MX plan, recently modified the Dense Pack plan from a 4.5- by-5-mile trapezoid configuration to a long, slender 1-by-14-mile column. Some Pentagon planners might say this change significantly improves the missiles' survivability; it seems to me someone is grasping for straws.

The beauty of Dense Pack is supposed to be that a stream of Soviet warheads would be unable to take out all the MX missiles in this closely spaced configuration because radioactive dust and debris from the explosion of the first Soviet missiles would deflect or destroy the other Soviet warheads. Defense experts call this "fratricide" -- one warhead killing its brother warhead. The hope is that MX would survive a first strike and then be able to return the fire.

But, unfortunately, experts also point out that Dense Pack has distinct disadvantages that call into question its very survivability. Physicist and military consultant Richard Garwin said the Soviet Union would be able to "pin down" the MX force for up to five hours by exploding nuclear warheads one after the other high above the Dense Pack field.

The Soviets also could counter Dense Pack by producing "earth-penetrating" warheads that would burrow into the earth near their targets and explode or, alternatively, by simultaneously exploding a relatively small number of massive-megatonnage warheads that would obliterate the entire field. In fact, the Defense Department's own consultants estimate that the Soviets may well have the ability to defeat the system by such methods in the early 1990s-- shortly after MX's expected full deployment. Dense Pack would then be obsolete, and a new deployment method would be required, raising the same difficulties we face today.

So why does the Pentagon seek a missile system, at a cost of at least $35 billion (as we face $200 billion budget deficits) that cannot be deployed until the late 1980s, and even then is only marginally less vulnerable than our current Minuteman missiles?

One Pentagon argument is that Dense Pack will present the Soviets with high costs in order to defeat the system. But the history of nuclear arms has shown that it is cheaper to defeat a weapon's defense than it is to defend that weapon. And with the Soviets' traditional willingness to meet their defense needs, there is little reason to believe they will not meet the MX challenge.

Two, the Defense Department also says it could eventually deploy an antiballistic missile system around the MX sites to shoot down Soviet warheads before they explode. But such an ABM system is limited by treaty at least through 1983. Such a system also would add another $12 billion or so to the cost of MX. And even if an ABM could be made to work and the treaty were to lapse, it would be far cheaper to use ABM to protect our existing Minuteman missiles, whose new MK 12A warheads have made them a very credible nuclear counterforce.

Despite MX's functional shortcomings and its price tag, many in Congress, the Pentagon and across the country continue to press on. Sadly, it seems that for some, a $35 billion missile that doesn't work is just the security blanket they need. Perhaps nowhere in American politics is levelheaded common sense more often overridden by ideologically motivated fear than in the defense arena. The ideological left abhors defense spending and promotes disarmament at all costs. The ideological right abhors Soviet aggression and promotes an arms race at all costs.

Not known for my dove feathers, I was struck by this ideological dichotomy in late September, when one of my Senate colleagues charged that my amendment to delay MX production until a proper basing mode was selected would have the Soviets "dancing in the street in Moscow." To remind you: my proposal didn't call for unilateral disarmament, it didn't call for surrender, it didn't even put an end to continued MX research and development. Yet the "dense pack" of MX supporters dances pirouettes with its rhetoric.

Careful, pragmatic and thoughtful decision- making is required if we are to maintain a strong, credible defense posture. Our economy has no room for procurement of a Pentagon wish list. And the often hard-line rhetoric of the administration should be replaced by performance.

There is a wide range of defense improvements that must be made on both the strategic and conventional fronts. MX is neither necessary nor an asset to such improvements. The Soviets would love nothing more than to see us throw away billions of dollars on a system that could be easily countered.

If we are concerned about ICBM vulnerability, we should commit ourselves to stepping up the difficult-to-detect Trident submarine force armed with highly accurate D5 missiles, and moving ahead with the Stealth bomber and air- and sea- launched cruise missiles. And nothing could show Moscow more U.S. resolve in redressing the unfavorable military balance than proper maintenance and equipping of our conventional forces, combined with deployment of the Pershing II and ground-launched cruise missiles. We are spending the store on large-ticket items, while our conventional fighting ability gets shortchanged.

If this month's election provided any message, it is that the American voter is looking for moderation and balance in government. Military spending is no exception.

After all is said and done, the MX Dense Pack is a weapons system that just doesn't work, and it costs a lot to boot. Throwing good money after bad has never made such sense, and with MX it makes no sense at all.