The Kremlin's chief specialist on American affairs declared today that despite tensions between the Soviet Union and the United States, which he blamed on the Carter administration, "the strengthening and deepening of detente has a future" because U.S. public opinion strongly supports it."

The lengthy article in the Communist Party newspaper Pravda by Dr. Georgi A. Arbatov, director of the Institute of U.S.A. and Canada Studies, is the most authoritative public reaction to date by the Kremlin to the speech President Carter delivered July 21 in Charleston, S.C., laying out long-range American policy goals in relations with the Soviet Union.

The article, spread across the bottom of two inside pages of Pravda, delved into American social history, politics, and weapons policies while setting forth Arbatov's views on the state of Soviet-American relations. Arbatov, a chain-smoking Communist Party veteran whose baldish head and heavily lidded visage is a familiar sight on Soviet television, is a personal adviser to Soviet leader Leonid Brezhev on the United States.

Western diplomatic sources here said the Arbatov piece is noteworthy in that it continued a Soviet policy of refraining from personal attacks on Carter, which diplomats said began immediately after the Charleston speech.

Before that speech, the many press organs of the Kremlin poured forth a steady diet of criticism -- some of it sharply personal -- against Carter and his policies. In the past week the Russian-language press, while keeping up its denunciations of the President's policies, has noticeably toned down its remarks about Carter himself.

Arbatov's article took issue with parts of Carter speech yet did so with unusual restraint. The article found broader reasons to criticize Carter, yet temporized on some of those points, too.

For example, Arbatov wrote that "some paragraphs of the speech in Charleston would be estimated as positive." Yet, he found serious difficulty with a key passage from the address in which the U.S. President sought to signal both Soviet leaders and Western allies that the administration is concerned that Soviet expressions of anger over the state of Strategic Arms Limiation Talks might be based move on propaganda than on substance. The President had declared:

"To be frank, we also hear some negative comments from the Soviet side about SALT and about our more general relations. If these comments are based on a misconception of our motves, we will redouble our efforts to make them clear. But if they are merely designed as propaganda to put pressure on us, let no one doubt that we will perserves."

Arbatov wrote: "In light of what has happened to recent relations between the two countries, that statement of the President evokes at least surprise." He reiterated the standard Soviet explanation its outright rejection of proposals made in March for strategic weapns cutbacks by Secretary of State Cyrus Vance: "They were rebuffed precisely because their meaning was well understood as an attempt of the United States to achieve one-sided advantage. The President's thesis about propaganda efforts doesn't merit criticism."

Declaring that success can come only when negotiators take into account the interest of American and Soviet people as well as all other people." Arbatov wrote that good relations call for "real efforts on both sides."

The Kremlin's displeasure with Carter began almost from his first weeks in office, when he spoke out in defense of human rights activists inside the Soviet Union and offered such gestures of support as writing a letter to Andrei Sakharov, the nuclear physicist who won the 1973 Nobel Peace Prize for his human rights activities.

Soviet displeasure spread to include the March SALT talks, the President recent decision to deploy the technologically advanced cruise missile, and the emergence of the neutron bomb which Carter amy deploy in Europe.

Arbatov touched on these concerns in his article, calling somewhat sarcastically for the need of clarification of the American position on a number of issues. For example, to make compatible the striving of the United States to achieve theoretical limitations on arms reductions with the recent decisions on deploying the strategic cruise missile and the neutron bomb. This is an obvious decision about the start of a new, dangerous round of the arms race.

"It would be advisable also to make clear how to square the call emphasizing mutual peace and cooperation . . . with the activation of anti-Soviet pro-paganda (via) Radio Liberty and Radio Free Europe, which were created in the years of the Cold War."

Arbatov made these other complaints:

The political atmosphere between the two countries has lately deteriorated as a "direct result of anti-Soviet propaganda [and] attempts ot interfere in internal affairs of the USSR and other socialist countries under the pretext of the defense of human rights."

The United States is to blame that "questions of Soviet-American economic relations are not being solved."

Some influential Americans have started to call the new relations between the two superpowers "controlled rivalry, and the term "cold detente's is used."