We put the following questions to six members of Congress:

1) At what point and under what circumstances should the United States use military force in the Persian Gulf region?

2) Do you think that this would necessarily -- or even probably -- lead to the introduction of nuclear weapons?

Here are their answers: Sen. John Tower Republican, Texas

Today the Soviet Union has the capability to disrupt the flow of oil from the Persian Gulf, and the United States cannot prevent it. Although such as action on the part of the Soviets appears unlikely in the near term, the stark fact is that their ability to do so leaves us vulnerable. We have no control over the Soviet decision process -- and are currently ill prepared to influence it.

Restoring our ability to protect militarily U.S. and allied interests in the Persian Gulf by deterring rather than by reacting must be our most urgent priority. We must have a constant military presence in the area. This presence should be complemented by a much improved overall military capability.

The objective of the strategy I favor is to present a credible deterrent by our presence and capability to disrupt and ultimately prevail over any Soviet efforts to shut off the flow of oil. At the same time, it is clear that for the United States -- an ocean power facing enormous commitments worldwide -- to pursue a strategy of opposing Soviet divisions one-on-one at every point on the globe, a strategy of attrition, is a losing proposition. We should adopt instead a military strategy of global "maneuver," a strategy built around capability to respond to Soviet aggression by attacking Soviet vulnerabilities that do exist.

No intelligent strategist should ever commit himself to, or foreclose, a particular course of action in hypothetical circumstances. That said, I believe that the pursuit of a strategy of "maneuver" would make clear that there are other means more effective and less destabilizing than the use of nuclear weapons in response to aggression in the Persian Gulf. Sen. George McGovern Democrat, South Dakota

In formulating policy for the Persian Gulf, we need to remember that those most responsible for the security of the area are the nations that comprise it. The best deterrent to Big Power intervention in the area is the nationalism -- of the Persian Gulf countries. Although in my view the likelihood of a Soviet military move against the Persian Gulf is now being vastly exaggerated by the Carter administration, we do not have to determine the probability of such as attempt to justify prudent measures to discourage it. American security requires above all that we develop a policy of conservation and alternative energy to break our perilous dependence upon OPEC oil. Meanwhile, it may also be prudent to maintain more effective American sea and air power in the Indian Ocean and the Arabian Sea as a deterrent to possible aggression and as a stabilizing influence in the region.

The capacity to intervene does carry with it the temptation to intervene. Discrimination is the key. A rapid deployment force would be of uncertain utility in revolutionary Iran (whose oil we have said we are going to do without anyway), and it would be obvious insanity to engage massive Soviet ground forces in areas close to their borders, such as Afghanistan. Not every political change of government threatens us; we have no right or vital interest in opposing every new Mossadegh.

Where quick U.S. intervention might make sense -- in the event, but only in the event of absolute necessity -- is in Saudi Arabia and the oil-producing emirates of the Arabian peninsula. Should these friendly governments be threatened either by the "outside force" cited by President Carter or by serious internal threat, the United States and our allies should have the capability of coming to their support if our help is requested.

I do not expect a Soviet military probe into the Persian Gulf. And judging from past behavior, Soviet enthusiasm for nuclear war is no greater than our own.

I can see no circumstance except a sudden desire to end human life on this planet that would justify the use of nuclear weapons in the Persian Gulf. Rep. Millicent Fenwick Republican, New Jersey

The point at which the use of military force would be justified in the Persian Gulf depends on two conditions: whether the United States has a firm commitment to participate on the part of our NATO allies and whether the states in the area are in agreement. The point that would make consideration of armed force necessary would be the movement of the army of the Soviet Union down into Iran or into some other area near the Persian Gulf.

The reason armed force would be justified is that 30 percent of our oil imports -- roughly 15 percent of our total oil consumption -- comes through the Strait of Hormuz at the southern end of the Gulf. Fully 50 percent of the consumption of our European allies and 75 percent of Japan's oil consumption also comes through the Strait. The economies of the whole industrialized world would be in imminent danger should the Soviet Union control the oil of the area. Also in jeopardy would be Egypt, Israel and Turkey, which is a member of NATO.

I do not believe, however, that such a confrontation would lead to a nuclear war. The combined NATO aimies would have formidable conventional arms. Supply lines from Europe would not be overlong. The question poses an unthinkable outcome of a conflict that there is very reason to believe we may never have to face. Only the unwillingness to do so will make it likely. Sen. Sam Nunn Democrat, Georgia

I do not believe that it is wise to specify in detail the circumstances under which American military power would be employed in the Persian Gulf. Much would depend on the nature of the threat, whether it was external or internal, the geographic location of the country threatened, and its capacity to defend itself and its willingness to accept American assitance. Obviously, the more direct the threat to Western oil supplies and related sea lanes of transportation, the more necessary and likely the use of American military force would be.

Our challenge in the Persian Gulf is to devise a military and political posture capable of deterring threats to our vital interests. Such a posture must rest on close cooperation with our allies, including Western Europe and Japan, to strengthen the position of the free world in the Indian Ocean area. It goes without saying that we should take every possible step to reduce our dependence on imported energy. To pretend, however, that we can become completely independent in the near term, or to pretend that the United States has no vital interests in the Persian Gulf except its own oil supply is to ignore the inescapable fact that Soviet domination of the Persian Gulf, even with an energy-independent America, would threaten the fabric of our alliances and our vital interests throughout the world.

I do not believe that either geography or likely military scenarios in the Persian Gulf region would dictate a military strategy based on the use of nuclear weapons. We must be aware, however, that any military confrontation between the Soviet Union and the United States inevitably creates the danger of escalation and could spread to other parts of the world. Rep. Les Aspin Democrat, Wisconsin

If there were a revolt in some Gulf country that might upset our access to oil -- a revolt strictly internal, not involving the Soviet Union -- we probably should not respond militarily. First, the local work force could destroy the oil-field equipment and cut off our access to oil for a very long time. Second, an invasion would alienate most other countries (as the Soviet invasion of Afghanistan has alienated many Moslem countries) and probably help the Russians extend their influence in the area. In short, the plan would backfire.

If, for another example, the Soviets should block the Strait of Hormuz, such action would directly threaten our interests; the use of force would be an appropriate response -- indeed, the Soviet action would constitute a declaration of war.

A more complicated scenario: Iran falls apart politically, with armed factions in different provinces. The Soviets amass divisions on the Soviet-Iranian border and finance some of the squabbling factions. This involves the Soviets and our oil -- but would the use of force, say a preemptive occupation, have much utility? Probably not.

We should alter our defensive forces so that we can, to the maximum extent possible, avoid having a fight a war in the Gulf. This means building up naval forces in the Indian Ocean, reaching agreements on the use of base facilities in the event of crisis, working more closely with governments in the region and improving mobility (e.g., implementing some sort of "rapid deployment force").

To the extent that we are unable to fight with properly deployed and configured conventional forces, the greater the chances that we would have to resort to nuclear threats -- and thus the higher the chance of nuclear war. Rep. Paul Findley Republican, Illinois

The United States should use military force in the Persian Gulf only if prudent non-military means have been exhausted -- a point that certainly has not yet been reached -- and even then the United States should insist that other major powers join us in any application of force.

At the same time, we should focus urgently on non-military measures. For example, the simple and sane step of the United States' beginning talks with the Palestine Liberation Organization and speaking up for self-determination for the people living in the West Bank would do more to turn the tide against Soviet advance in the Gulf region than the arrival of a half-dozen aircraft carriers and 10,000 Marines.

For decades, Arabs have, rightly or wrongly, felt that the major threat to their security comes not from the Soviet Union but from Israel, a country that, with the aid of U.S. arms, today occupies Arab land in Egypt, Jordan, Syria and Lebanon. The fact that these Arab states contributed to -- and in some cases provoked -- Israeli occupation is today lost in history.

The United States could also wisely make plain that it has no intention of trying to put another shah in power in Iran.

The sobering truth is that, today, not a single Gulf state is eager to have U.S. military forces on its soil. The revolution in Iran has created ferment and fear in neighboring states. Ruling classes fear that the arrival of U.S. military forces would trigger upheavel, because U.S. military power is linked so closely in Moslem perceptions with oppression. Arab states see the Soviet threat as more distant, less real than the Israeli threat. Israel uses U.S. weapons to continue its occupation of Arab land. The ongoing, unresolved Arab-Israel problem is profoundly linked to instability in the Gulf region, and so far the United States has not faced that fact.