Zbigniew Brzezinski's June 7 article in The Post's Outlook section contains old ideas in new wrappings. Although cloaked in the urgency of U.S. operations in the Persian Gulf since the USS Stark was struck by Iraqi missiles, his proposal to increase the forces in the Persian Gulf or elsewhere, while reducing our forces in Europe, has fundamental flaws.

Brzezinski says that because our NATO allies will not help us enough with global responsibilities, we must withdraw 100,000 troops from NATO Europe, the strategic region where he judges a direct military threat "least likely," and build more capabilities for the Gulf, "the region in which a challenge is most likely."

But it is the very presence of our forces in NATO Europe that has ensured stability there and allowed critics to call it the ''least likely'' threat area. Remove that strength and it becomes the ''most likely'' area to be attacked.

The fact is that our own forward-deployed forces, with our allies', provide today, and will need to keep providing, the combat power to repulse an attack by the Warsaw Pact until planned reinforcements arrive.

Even were we to assume a need for additional forces for the Gulf region, we already possess some 20 U.S. active and reserve divisions that are not already deployed overseas or planned for Southwest Asia. With these, what possible logic would there be in taking forces from Europe?

Furthermore, it is difficult to see where all the budget "savings" that could underwrite additional air- and sea-lift capacity would come from. It would cost some $5 billion just to bring 100,000 troops home and quarter them here. The airlift capability we would need to get them back to Europe in 10 days (to keep our NATO commitments) would be $20 billion to $25 billion with prepositioned equipment, and about $100 billion without. For deployment to Southwest Asia over 30 days, the cost would be about $40 billion for acquisition and $3.5 billion annually for operations and maintenance.

Brzezinski implies that phasing the withdrawal and converting forces from heavy to light divisions would produce important savings. He offers no specifics. Contrary to the impression he leaves, we have been creating additional light forces over several years and are approaching completion of our program. Given the continuing Soviet heavy force threat, further conversions do not appear desirable.

In short, the problem is not how to obtain additional combat forces for the Mideast. The real problem is that weakening the defenses of Europe would gravely weaken us.

I doubt that a troop withdrawal would increase Europeans' incentives to do more for their own defense. It would convey a signal that the United States believed the Soviet threat in Europe was diminishing. It could only reinforce existing pressures to cut back on defense expenditures.

Brzezinski's pronouncement that NATO has now condemned itself to the status of "regional alliance" is curious. NATO has always been a regional alliance, avowedly and by treaty. This, while regrettable, is understandable, but it does not preclude cooperative effort in the Persian Gulf nor prevent us from continuing to work toward a greater sharing of responsibilities in the Gulf region by individual allies.

To talk of weakening Europe's conventional strength at a time when we are about to remove part of Europe's nuclear deterrence seems to me to court the worst kind of danger.

Brzezinski's proposal could scuttle conventional arms reduction negotiations, at a time when, given progress in the INF talks, conventional balance instead of the present huge imbalance in the Soviets' favor takes on even greater significance. The mutual thinning out of forces in Europe that he envisions will be possible only if NATO maintains and strengthens its conventional forces to provide real incentive for the Soviets to negotiate.

As for his suggestion of a "tank-free zone" in Central Europe, his focus on Soviet offensive potential is commendable. But the Soviets could simply withdraw tanks a few miles, or even farther, while West Germany would be in effect a demilitarized zone. This is a solution that would not change Soviet capabilities, while the potential increase in warning time to NATO would be more than offset by the head start the Soviets would gain in any subsequent buildup.

The writer is secretary of defense.