During two months of crumbling relations, the United States and the Soviet Union have sampled the damage that each can inflict on the other short of an outright confrontation.

"It has been a sobering experience," said a senior American policymaker, looking back on the bristling exchanges about Africa, spies, dissidents, trade and the basic meaning of U.S.-Soviet detente.

Each superpower "got a sort of whiff of grapeshot, so to speak," another high official said, "and neither side liked it very much."

This most resounding clash between the Kremlin and the Carter administration, which has yet to run its full course, is too recent for full assessment, U.S. strategists said in a series of private interviews.

By contrast, one official said, the administration's first public bruising encounter with the Soviet Union in March 1977 over the strategic arms limitation talks (SALT) was "one-dimensional." This time around, he said, "you really had to weigh in the balance the whole of U.S.-Soviet relations."

Although "both sides have pulled back a bit," as one official expressed the viewpoint inside the administration, many of the same volatile issues will recur next month and beyond.

They include: new SALT negotiations between Secretary of State Cyrus R. Vance and Soviet Foreign Minister Andrei A. Gromyko in New York; the unresolved struggle over human rights in the Soviet Union; continuing U.S. concern about the use of Soviet-Cuban power in Africa, and the prospect for expanding tension in the American-Chinese-Soviet triangle.

There are two preoccupying issues inside the U.S. diplomatic-security bureaucracy. One is the direction Soviet policy will take. The other is the future course of American strategy and tactics.

Recurring phrases in the upper echelon of the Carter administration hierarchy are that the president will "pick and choose" among his advisers on the actions he will take, and that he is "not locked in" to any single "line."

This should not be overlooked, insiders caution, because of Carter's decision to reaffirm the primacy of Vance, rather than national security affairs adviser Zbigniew Brzezinski, as his chief co-spokesman on foreign policy.

Over the last two months, Carter also accepted most often - but not totally - the more moderate responses to Soviet actions advocated by Vance and his associates, over the stiffer, more militant ripostes championed by Brzezinski and his National Security Council staff. But this offers far less assurance of an immutable pattern, both sides say in private.

Some of the more combative challenges to the Kremlin advocated on the Brzezinski side, such as counteractions to checkmate Soviet-Cuban power in African, were blocked by obstacles beyond the reach of the White House. Carter's avoidance of them therefore did not necessarily signify what decisions he would have made if his choices of action were less restricted.

As a consequence, the State Department's considerable satisfaction over the enhanced prestige and influence currently enjoyed by Vance is mitigated by a hallmark of the Carter presidency; where he has been on an issue is no guarantee of where he will go.

Brzezinski and his associates therefore are not feigning in their insistence - and Carter's - that Brzezinski has not been overrun, squashed or "muzzled" by the president. The competition forthe president's ear continues in full force, senior State Department officials agree.

The president virtually was compelled to resolve the question of "who speaks" for the United States. The credibility of American foreign policy was disintegrating in the cacophony of voices at the top of the administration, confounding allies as well as adversaries.

There is no illusion among senior officials at State, sources there said, that the president's overriding purpose was to demonstrate "control."

"The objective was not to boost Cy or to put down Zbig," said one highranking official in a typical comment. "Nor was it a choice between 'hard' or 'soft' lines. Carter wants two strong advisers."

It is the greatest hope, of course, at the State Department that its "moderate approach" will prevail. Some senior insiders express "confidence" that it will, but others do not minimize their apprehensions about the policy struggles ahead.

One Vance aide said bluntly: "It will be an agonizing process."

Carter used a form of "split decision" response last month to outraged American demands for retaliation against the trials and imprisonment of Soviet dissidents Anatoly Scharansky and Alexander Ginzburg, leading symbols of his human rights campaign. But U.S. actions were very restrained.

With the Congress and many of his advisers divided, Carter sent Vance to Geneva for nuclear arms control talks, even though the Moscow dissident trials were timed to overlap with the negotiations on SALT. After his talks with Gromyko, Vance met with Scharansky's wife, Avital. [An Associated Press-NBC News poll published yesterday reported that among those with knowledge of the dissident trials, three-fourths agreed with the president that SALT negotiations should continue despite Soviet violations of human rights.]

American retaliation to the dissident trials has been limited to halting the previously diminishing number of trips by official visitors to the Soviet Union, and to tightening restrictions on sales of American technology. The trade controversy continues to be one of the stormiest.

Carter gave a measure of satisfaction to his divided counselors on trade restrictions: Brzezinski's staff and several influential members of Congress, notably Sen. Henry M. Jackson (D-Wash.), were pressing for sweeping restrictions on trade; Vance, Commerce Secretary Juanita M. Kreps and Treasury Secretary W. Michael Blumenthal were vigorously opposed.

Last month, Carter canceled the sale of a large computer to Tass, the Soviet news agency - equipment that critics protested could be diverted to other purposes. But last week, Carter authorized the sale of a disputed portion of a $144 million plant to produce oil well drilling bits in the Soviet Union.

Coming up for decision are much more difficult choices.

In the weeks ahead, Carter must make decisions on the instructions Vance will carry into the next round of SALT talks with Gromyko late next month. At the same time, in preparation for the new U.S. defense budget, Carter faces major decisions on weapons systems and U.S. military strategy, some of which overlap significantly with the nuclear questions to be resolved with the Soviet Union.

It has served Soviet purposes, and the so far prevailing moderate approach inside the administration, to "insulate" U.S.-Soviet arms control negotiations from outside tensions.

In addition to pursuing the SALT negotiations "seriously," the Soviet Union in June offered a proposal that moved markedly closer, American officials agree, toward the Western position for a potential breakthrough in long-stalled negotiations for mutual reduction of forces in Central Europe, although important differences remain.

A recent U.S.-Soviet conference in Helsinki also reported marginal progress toward a more remote goal, possible limitations on each superpower's sale of conventional weapons to other nations - an untouched target in the world arms race.

Also, on marginal, positive side of the accounting, administration strategists note that a potential existed for Soviet-Cuban obstruction of the recent Western progress toward resolving racial conflict and independence in Namibia (Southwest Africa), and that was not exploited by Moscow. Concern does continue inside the administration, however, about the continuing Soviet-Cuban potential for disrupting Western attempts to resolve the larger Rhodesian racial warfare.

It is on the human rights front that the U.S.-Soviet outlook continues to be especially grim and tense, in the increasingly politically volatile climate of the approaching American congressional elections.

The Soviet Union may want to calm down American reaction to the extraordinary charges of "slander" brought against two Moscow-based U.S. correspondents for writing about a Soviet dissident, U.S. sources speculate.

That is a civil suit against New York Times reporter Craig R. Witney and Baltimore Sun reporter Harold D. Piper. Their case is of a different magnitude than the manhandling and arrest of U.S. businessman Francis (Jay) Crawford by Soviet security forces.

Crawford, International Harvester's representative in Moscow, was seized in June and charged with currency manipulation. The Soviet Union has all but unofficially acknowledged that was retaliation for charges of espionage brought against Valdik A. Enger and Rudolf P. Chernyayev, two Soviet employes of the United Nations arrested in May in Woodbridge, N.J.

"Two can play that game," Gromyko angrily told Vance in New York after the Russian arrests. To the Kremlin, publicly charging the two Russians broke the rules of the game for handling accused spies. The United States maintains it did not break precedent, because the Russians held no diplomatic immunity entitling them to leave the country quietly.

Many U.S. diplomatic and security specialists, it was learned, advised against prosecuting the two Russians, cautioning that the Soviet Union holds a different view of the rules and precedents.

The U.S. decision to prosecute the Russian pair is attributed by insiders to the advocacy of Attorney General Griffin B. Bell, anxious to uphold "legality" and the prowess of the FBI, reinforced by White House political advisers.

Soviet retaliation "was certain," a veteran U.S. diplomat said last week. "We put them [the KGB, the Soviet security apparatus] in a position of being at their worst - and they are being at their worst - and that can be pretty damn uncivilized."

The U.S. position is that it "will never equate" an "innocent businessman" with "two Russian spies." Nevertheless, in late June the United States agreed to free the two Russians from jail pending trial, in turn for the similar release of Crawford.

If no diplomatic deal is made, both cases are expected to come to trial in the two countries in mid-September. And that, U.S. diplomats glumly note, would stimulate new tension just before the next round of U.S.-Soviet nuclear arms control talks.