Paul C. Warnke's two days before the Senate Armed Services Committee last week were the first forum for what promises to be the major foreign policy debate in at least the early Carter administration years - how to deal with the Soviet Union.

The interrogation of Warnke ranged over three principal areas of concern but the underlying questions - How much defense is enough? and How disarmament proposals should be approached? - were rarely addressed directly.

Instead, the three major preoccupations were whether the United States is in danger of letting down its guard, Warnke's credibility and whether he sufficiently appreciates the Soviet threat, and Warnke's past opposition to several strategic weapons systems.

On the first, some critical senators appeared not to agree with one of the often-repeated points of President Carter's nominee to head the Arms Control and Disarmament Agency and negotiate with the Soviets.

"I think we have to recognize that any arms control agreement is going to have to be fair to both sides because, otherwise, there is no way in which it can endure," Warnke said.

"If, for example, we were to end up with an imbalance on one side or the other, the side that found itself at a disadvantage would have to repudiate the treaty in its national interest."

"Rough equivalence will have to do," Warnke said, noting the phrase is the one used by the Joint Chiefs of Staff.

But some senators' words revived nostalgic memories of a time when U.S. nuclear superiority was unquestioned.

"I think we have created a monster," Sen. Jake Garn (R.-Utah) said. "At the end of World War II they (the Soviets) were simply not a world power; we were." The United States had "the possibility or potential at that point of ruling the world . . .," Garn remarked.

"What you are suggesting, I think," Warnke replied, "is that the entire process of arms cntrol negotiation is futile."

Garn said he only wanted "tough bargaining." But he noted that he had called detente another word for appeasement during the Ford administration.

For Garn, Sen. John G. Tower (R.-Tex.) Sen. Barry Goldwater (R.-Ariz.) and others, Warnke came before them as a symbol of a policy of weakness pursued for years by Washington and now posing a danger of leaving Americans behind in the arms race with the Soviet Union.

The senators drew from Warnke repeated admissions that circumstances have changed and therefore some of his earlier positions are outdated, but he would not concede the positions had been wrong. A typical exchange came after Sen. Strom Thurmond (R.-S.C.) quoted an earlier Warnke statement.

Thurmond: "So you said none of those are justified. I believe that is your testimony, isn't it?"

Warnke: "It was, and I might point out, senator, that this was 1974."

Over and over, Warnke made statements that hawkish senators said they agreed with. But, the senators almost pleaded with Warnke to tell them he had changed his position.

"It's all right to have a change of mind," senator after senator told Warnke, trying to coax him out of his eloquent, lawyerly, patient and sometimes jaunty assertions that, although they might see a charge, none was there.

The tone was often like this exchange between Warnke and Sen. Henry M. Jackson (D-Wash.) over Warnke's insistence that this earlier proposal that the number of U.S. tactical nuclear weapons in Europe could be cut is not inconsistent with his testimony last week.

Jackons: "What did you advocate cutting?"

Warnke: "I suggested we could get down to something like 1,000 tactical nuclear weapons in Europe."

"Jackson: "From 7,000 to 1,000?'

Warnke: "From 7,000 to 1,000, yes. We are now, however, in a negotiating situation in which the tactical nuclear question has been raised as one of the items for negotiation. I believe it ought to be handled now at the MBFR (mutual and balanced force reduction) talks."

Jackson: "You advocated that cut during the process of the negotiating stage; is that not true?"

Warnke: "That was before any consideration had been given to tabling a proposal with respect to tactical nuclear weapons."

Jackson: "Were we not in the MBFR and SALT (strategic arms limitation talks) negotiations at the time you made that recommendation?"

Warnke: "Yes, we were."

Jackson: "So you are contradicting yourself now?"

Warnke: "No. I am saying that we had not tabled a proposal which tied tactical nuclear weapons to the question of troop withdrawals."

The Armed Services Committee succeeded in putting Warnke on record as being aware of recent Soviet gains in relative nuclear strength and as recognizing the need to be a tough negotiator.

Sen. Jesse Helms (R-N.C.) obtained promises that a member of the Joint Chiefs of Staff would be present throughout the bargaining with the Russians.

Sen. Howard Cannon (D-Nev.) Pressed Warnke on tactical nuclear weapons and U.S. troop strength in Europe.

"I would say, senator, that the present time would not be an appropriate time to take our tactical forces from Europe, except for those overly exposed and therefore presenting a risk," Warnke replied.

"When did you come to that conclusion" Cannon asked.

"In light of the Soviet buildup," Warnke replied.

"When? Since your nomination or . . ."

Well, before my nomination," Warnke said.

One Warnke supporter likened Jackson's and other senators' desire to find an inconsistency in Warkne's position to George Santayana' definition of a fanatic as "as a man who redoubles his effort as he loses sight of his goals."

In view of the expected Senate confirmation of Warnke, he suggested, the committee should be content with the commitments its members received from him.

Warnke's foes, who will take another swing at his record during a committee hearing Monday believe that if they can demonstrate he changed his positions only to win confirmation they can gather enough opposition to block the nomination.

Another block of time was spent attacking Warnke for his past arguments against some strategic weapons systems, principally the B-1 bomber, the Trident missile submarine, the sea-launched cruise missile, and the deployment of multiple warheads (MIRVs).

Warnke made clear at the outset and explained repeatedly that his opposition had always been based either on the availability of an alternative system he thought could be more cost effective or because he thought they were dangerous to the national security.

"A MIRVed world has not contributed to our security," Warnek said, because it is impossible to tell how many warheads rest on a MIRVed missile.

In reply to Thurmond's suggestion that he would be too ready to bargain away a weapons system which he had at one time opposed, Warnke said:

"I am not in favor of throwing away a system that has been developed and deployed. I think that an alternative might have been preferable, but I certainly don't recommend scrapping a system that has cost us billions of dollars to develop and deploy."

Backing Warnke throughout the hearings and drawing some of the senators' fire was President Carter, who has angered several Democrats and Republicans by asking them to approve a self-confessed dove, Warnke, and by failing to give hawks any prominent national security affairs jobs.

The President has committed his prestige to Warnke and telephoned about a dozen senators to urge approval of the nomination.

The fears and hopes that the nomination has aroused were captured in an exchange between Helms and Warnke.

". . . How can we negotiate in good faith with an adversary that does not share any of the values of decency and honor held by most civilized people in this world?" Helms asked.

Warnke acknowledge the dangers and said: "What we can be confident of, however, is that nations pursue their own self-interests."

There are two choices for both nations, he added, continuing arms competitionand increasing risk, or arms control.