The decision by the leaders of the United States and the People's Republic of China to normalize their relations is a long-awaited international event with powerful repercussions far beyond the shores of either nation.

The timing-on the eve of a likely U.S. Soviet agreement on a new strategic arms limitation treaty (SALT) and a U.S.-Soviet summit meeting-represents a determination by the White House to balance its relations with the two rival giants of world communism.

President Carter's move, in this sense, is a continuation of the triangular Washington-Moscow-Peking diplomacy that was started seven years ago by Richard M. Nixon and Henry A. Kissinger.

On the Chinese side, the decision to move in swift and determinded fashion to full ties with WASHINGTON IS THE CAPSTONE OF A STUNNING DIPLOMATIC OFFENSIVE THAT BEGAN EARLY THIS YEAR.

THE FUNDAMENTAL DECISION BY THE PRAGMATIC LEADERS WHO FOLLOWED MAO TSE-TUNG WAS TO TURN OUTWARD FOR INTERNATIONAL ASSISTANCE, CONTACTS AND TECHNOLOGY IN THE INTEREST OF SWIFT DEVELOPMENT OF THE WORLD'S MOST POPULOUS NATION. AFTER MORE THAN A DECADE OF NEAR-ISOLATION, THE CHINESE LEADERSHIP SUDDENLY BEGAN AGGRESSIVE PURSUIT OF CLOSE RELATIONS OR ALLIANCES NATIONS. THE NEW WASHINGTON CONNECTION IS THE NATURAL OUTGROWTH OF THIS DRIVE.

CARTER TOLD REPORTERS LAST NIGHT THAT HE DOES NOT THINK THE U.S. move toward Peking will have "any adverse reaction at all" on the SALT talks with the Soviets, which are expected to come to a climax next week in Geneva. Other top officials said the Soviets expected the U.S. move. The officials gave no indication that Soviet Ambassador Anatoliy F. Dobrynin protested the decision when called to the White House at 3 p.m. to be informed in advance.

Normalization of relations with China was one of the 10 major diplomatic objectives set down by Carter and his close advisers as he came to the presidency nearly two years ago, and Carter has consistently cited completed diplomatic ties with Peking as his goal.

In practical terms, however, Carter appeared to be blocked by his commitment to the well-being of the people of Taiwan and by the domestic and international uproar which would result from seeming to "abandon" the longtime U.S. ally.

It was far from clear last night that the United States has obtained any assurance from Peking about the future of Taiwan. High U.S. officials who briefed reporters at the White House reporters at the white House repeatedly refused to say, whether, as is widely believed and reported, the United States had asked Peking to give some kind of assurance that Taiwan will not be taken by force.

At one point, an official said the matter might be clarified by a statement being issued simultaneously in Peking. But according to news agency reports, the Chinese statement said on this point only that Taiwan is "entirely China's internal affair."

Carter told reporters that "we have maintained our own U.S. position firmly" and he declared that "the interest of Taiwan has been adequately protected."

Officials expressed confidence that the continuing relationship of the United States and China, and China's historical patience and desire for friendly relations in the region, will assure a peaceful furture for Taiwan. They also stated several times that China is aware of the U.S. statements about the continuation of close relations with Taiwan and "they do not take exception."

One of the most delicate matters is the question of future U.S. military sales to Taiwan. While nothing was said about this in Carter's speech for the joint communique issued last night, U.S. officials said that "the United States will give Taiwan access to arms of a defensive character on a restrained basis" after diplomatic ties are ended.

Secretary of State Cyrus R. Vance went to China in August 1977, but seemed to get nowhere in his attempts to explore ways to solve the Taiwan question by an arrangement acceptable to Washington and Peking.

The intensive phase of U.S.-Chinese courtship in this administration began with the Peking trip in May this year by presidential national security affairs adviser Zbignew Brzezinski, whose anti-Soviet attitudes and rhetoric delighted his host-and set off alarm bells in the Kremlin about a Washington-Peking alliance.

It was said then that Brzezinski did not go to China to negotiable on normalization, and there were only the barest hints in the intervening months that major moves toward normalization of relations were afoot.

On the hand, trade, exchange and governmenta and private contacts of all kinds flowered between two nations. The United States approved high technology sales to China, sent Cabinet members on Peking missions, and withdrew its traditional objections to the sale of arms to China by European allies.

Officials revealed last night that secret negotiations about normalization had begun in Peking last June, shortly after Brzizinski had conveyed Carter's determination to move ahead. But they said the negotiations were given new impetus only 10 days ago with what was depicted as new Chinese determination to move on U.S. terms that evidently had not been accepted in the past.

In an effort to avoid a repetition of the Nixon era diplomatic shock which disrupted relations with Japan, Carter personally telephoned Japanese Prime Minister Masayoshi Ohira. The Japanese having recently signed a peace and friendship treaty with Peking with U.S. blessing, are not expected to react adversely to the new move.

While credit was given to Vance and other State Department officials as well as to others, it is clear that the new opening to China is largely Brzezinski's affair. Like Kissinger before him, the national security affairs adviser seems to have taken on the role of super "desk officer" for chinese affairs.

While the White House went out of its way to say that the new moves are not directed against any other nation, it is doubtful that either the Soviets or Chinese will view them as an entirely neutral act in view of the tension between the two Communist giants. With triangular diplomacy restored, the already volatile international scene will be all the more uncertain in months ahead.