THE REAGAN administration's attitude toward nuclear weapons and nuclear war has profoundly alarmed millions of Americans. The unexpected explosion of public support for a nuclear freeze sends a message that is loud and clear: "Stop the arms race, we want to get off!" There is also deep frustration in the land about what can be done when the government in power is as inflexible as this one seems to be.

But something can be done -- by Congress. Of course the House and Senate cannot dictate national security policy to the executive branch. But with legislation, resolutions and the right kind of hearings, Congress can transform the political environment in which national security policy is made.

* That policy is now based on what we may call the Weinberger Doctrine:

* The United States must have the ability not just to wage nuclear wars but to "prevail" in such conflicts.

* By engaging in an arms race, the United States can force the Soviet Union to adopt policies more to our liking.

This doctrine was unveiled when the Five- Year Defense Guidance Plan, signed by Defense Secretary Caspar Weinberger, was leaked to the press last May. It has never been disavowed by the Reagan administration.

That document states that our nuclear forces must be able to "decapitate" the Soviet leadership, while we control the climb up the "escalation ladder." The plan expects us to "prevail" and to attain an end of hostilities on "terms favorable to the U. S.," though it neglects to explain with whom these terms would be negotiated.

The Reagan administration differs from all its predecessors in one important respect: The formulation and execution of defense policy is now in the hands of civilians who believe that this country really could "prevail" in a nuclear war. Weinberger's five-year plan heralds the triumph of a school of civilian strategists whose theories tell us as much about national security as astrology does about the nature of the heavenly bodies. No wonder the Joint Chiefs of Staff have had to become the restraining force in the Pentagon.

The Weinberger Doctrine is firmly based on misconceptions, some military, others political.

On the military side, it fails to recognize that any nuclear war -- no matter how limited -- could escalate to a strategic nuclear war. One can argue forever whether this escalation probability is 10 percent, or 50 percent, or 90 percent. But it is certainly not zero.

Once a strategic exchange begins, escalation to an all-out holocaust becomes very possible. Both human and technical factors point in that direction. In particular, the intricate systems that both superpowers use to control their nuclear weapons, and to watch their opponent, are highly vulnerable to attack. Hence the use of nuclear weapons to achieve any military or political objective whatever entails unacceptable risks. Nuclear weapons can only serve as a deterrent.

The political facet of the Weinberger Doctrine is even more remarkable. While American voters will never accept the arms race that it envisages, the doctrine will provoke a Soviet response that could last for a generation, because the dictatorship of the proletariat is largely immune to the desires of proletarians. The notion that the White House could compete with the Kremlim in extracting the sacrifices demanded by a more intense arms race is nonsense.

One might choose to simply await the inevitable failure of the Weinberger Doctrine. But while our leaders chase the mirage of nuclear superiority, opportunities that will never return are lost.

Propaganda notwithstanding, Soviet positions in three vital areas of arms control deserve serious consideration: on nuclear proliferation, weapons in space, and medium-range missiles in Europe. All have been rejected or ignored by the Reagan administration. All deserve the scrutiny of Congress.

The same holds for strategic arms control. Experts have noted that the much-maligned SALT II treaty, which is signed, is more advantageous to the United States than President Reagan's START proposal -- which has yet to be transformed into a draft treaty suitable for negotiation at Geneva. This paradox merits congressional inquiry.

After Hiroshima, the United States tried in vain to achieve international control over nuclear weapons. In retrospect it is obvious that Stalin was far too suspicious and power-hungry to allow America to be the only nation to possess such a revolutionary military technology.

In 1958 President Eisenhower announced that we were willing to negotiate a Comprehensive Test Ban Treaty (CTBT) outlawing all nuclear tests. This imaginative proposal went down with the U.S. spy plane shot down over Russia. No president since then has had both the wisdom and prestige required for so far-reaching a step.

By the time the 1963 treaty banning atmospheric tests was signed, the arms racers had gutted the Eisenhower concept: Testing just went underground. Had the comprehensive ban been adopted in 1960, the most destabilizing weapons in both arsenals -- the multiple warhead missiles (MIRV) -- would now be more primitive and less dangerous.

In 1974 President Nixon signed the Threshold Test Ban Treaty prohibiting underground tests larger than 150 kilotons -- some 10 times the Hiroshima bomb. It has not been ratified. President Carter made progress toward a comprehensive test ban. The Russians agreed to a network of seismic detectors on Soviet soil, and to some on-site inspection. But Carter did not have the political strength to capitalize on this. In July 1982 the Reagan administrtion announced that it would be the first U.S. government to abandon all negotiations towards a CTBT.

The evolution of the strategic balance is also instructive, because in advocating the Weinberger Doctrine the administration often rewrites history.

Last Nov. 22 President Reagan, while pointing to a chart, said to the nation, "Believe it or not, we froze our numbers in 1965 and have deployed no additional missiles since then." He neglected to say that since 1965, because of MIRV, the number of warheads carried by our submarines and land- based millies has grown from 1,700 to 6,200.

Reagan also said, "Many of our bombers are now older than the pilots who fly them," but he did not point out that, at this moment, they are being equipped with 3,000 incredibly accurate nuclear cruise missiles that can be fired from outside Soviet air defenses. Therefore no new high-performance plane, such as the B1, is needed to bomb the Soviet Union.

In brief, today our strategic weapons are far more numerous, survivable, versatile, accurate and reliable than in 1965. As the Joint Chiefs have said, they would not trade our arsenal for the Soviets'.

Since 1972 the Soviet Union has quadrupled its strategic warheads and greatly strengthened its European missile force. But we should remember that we have also made dramatic moves.

In 1960-65, the advent of Polaris submarines and Minuteman ICBMs produced a massive increase in the potency of our forces. That's why the administration uses 1965 as the base year in promoting its buildup; it does not mention that we then enjoyed a 10-to-1 advantage in warheads. And the recent Soviet buildup was certainly triggered by our earlier MIRV deployment.

Since 1945 every major weapons system was first introduced by us: hydrogen bombs, solid-fueled missiles, submarine-launched missiles, MIRV and cruise missiles. This record should be compared with Reagan's statement on Nov. 22: "You often hear that the U.S. and the Soviet Union are in an arms race. The truth is that while the Soviet Union has raced, we have not."

Both sides are racing. Neither seems able to learn that the race relentlessly undermines its security.

What can Congress do to stem this tide? Consider, first, that the administration has abandoned the test ban negotiations, and has evenn indicated a desire to renegotiate the Threshold Test Ban Treaty, because it claims we cannot verify Soviet adherence to the 150- kiloton limit. This contradicts the opinion of virtually all leading geophysicists. In any event, if that is really the president's concern, he should ask Congress to ratify the Threshold Treaty, whereupon both parties must hold joint test explosions to check the calibration of their seismic detectors.

But the current 150-kiloton limit is a red herring. All experts agree that underground explosions as small as 2 kilotons can be detected and distinguished -- with high confidence -- from earthquakes. A test ban with an exceedingly low threshold is verifiable.

Unfortunately, by now a comprehensive ban would have little impact on the superpowers' arms race. Soviet and U.S. warheads are already approaching the ultimate level of perfection. But a comprehensive ban would be a severe hurdle for nations trying to join the nuclear club.

Congress' committees should hold hearings on the detection of underground explosions and on the impact of a test ban on proliferation, with a view toward a congressional resolution calling on the administration to negotiate a Comprehensive Test Ban Treaty.

Next, note that the Weinberger Doctrine calls for "a strategic war-fighting antisatellite system," and states that "we must insure that treaties do not foreclose opportunities to develop these capabilities." So spending on the militarization of space is to grow faster than the defense budget as a whole.

Satellites are one of the few godsends to come our way since 1945. Their disappearance from the sky would dramatically increase the danger of nuclear war. They are essential to surveillance, communications and control.

Because the United States is an open society, and our forces are flung across the globe, satellites are more important to us than to the Russians. Should we stumble into a nuclear war, the negotiations that should follow (assuming the adversary had not been "decapitated") would be entirely dependent on satellites for communication and surveillance. All previous presidents, beginning with Eisenhower, have concluded that it would be to our advantage if no nation had any antisatellite capability.

During the Carter administration there were unsuccessful negotiations aimed at this goal. In August 1981 the Soviets proposed at the United Nations to prohibit the orbiting of weapons of any kind while permitting operation of the shuttle. This administration has not explored whether this the Soviets would extend this idea to a formal ban on the testing of antisatellite weapons.

As Sen. Larry Pressler (R-S.D.), chairman of the Senate subcommittee on arms control, has stressed, it is essential to prevent the testing of the new generation of anti-satellite weapons. For that reason he has proposed a mutual freeze on flight tests of such systems while negotiations take place. There is an urgent need for congressional hearings to explore the Pressler proposal and the administration's heedless militarization of space.

Third, recall that in December the new Soviet leader, Yuri Andropov, offered to halve the number of SS-20 ballistic missiles in Europe if we refrained from installing the new Pershing II and cruise missiles that NATO decided in 1979 to deploy in Europe to counter those SS-20s. Andropov contends that this would give the Soviets the same size force as the West, a conclusion he reaches by counting British and French missiles.

He has been curtly rejected by Washington, Paris, and London, and with somewhat less vigor by Bonn. The Reagan administration continues to insist on its "zero option," as though the Soviets could be expected to dismantle all of their rockets for a promise that we will not deploy ours.

These negotiations must be pursued vigorously. The placing of U.S. missiles on European soil would be highly divisive. Though we doubt the Russians are that shrewd, one must wonder whether their reckless SS-20 buildup was actually intended to provoke us into a response that would tear NATO apart.

Congressional committees should explore the long-term consequences of deploying hundreds of new missiles in Europe, asking how such deployments could possibly enhance Western security.

If the NATO nations really want to increase their security, they would do better to divert funds from nuclear weapons that could destroy them to conventional weapons that can defend them. Congress should weigh every funding request for nuclear weaponry against what the same money would buy in combat supplies, fortifications, pre-positioned equipment and the other humdrum needs of a sound and credible defense.

It is true that it is difficult for Congress to provide leadership in national security affairs, but it is also true that the administration is headed in a disastrous direction. The 1982 elections show that Americans do not want to go in that direction, like lemmings to the sea.

Congress can and should provide an alternative. It can withold funds from military programs that undermine our security. It can pass resolutions in support of the freeze and other critical arms control measures. And it can ratify SALT II and the Threshold Test Ban as executive agreements.