"Whether we like it or not," said Krishna Babla, an accountant watching the American election returns outside the U.S. Information Service's library in Dar es Salaam, Tanzania, early yesterday, "you're electing the president not only of the United States but of the world.

"We don't live in isolation here. People know that what happens in the United States can decide our future."

Around the world, ordinary persons as well as policy makers responded to the reelection of President Reagan in terms of its effects on their own countries' futures.

From the Middle East, Israeli Prime Minister Shimon Peres sent congratulations, calling Reagan a "great and sincere" friend of Israel, while Syrian President Hafez Assad sent Reagan "my hopes that the coming years will see a development in relations between our two countries." But state-controlled Damascus radio said it doubted that Reagan's reelection would bring any change in U.S. Mideast policy, which it called a failure.

Egyptian President Hosni Mubarak, in his message to Reagan, said, "We, in this vital part of the world, look forward with faith to a resumption of an active U.S. role to achieve peace." Egypt's Foreign Ministry, in a separate statement, called for a prompt revival of Reagan's September 1982 Mideast peace initiative, which called for establishment of a Palestinian homeland associated with Jordan on the Israeli-occupied West Bank.

A leading West Bank moderate, Mayor Elias Freij of Bethlehem, said "Palestinians should view the reelection of Reagan positively due to his pragmatic approach to the Arab-Israeli conflict."

In Tokyo, Japanese Prime Minister Yasuhiro Nakasone beamed as he told reporters outside his office that he was "very happy" with Reagan's "big victory." He added, "I have formulated a team with Reagan to work for peace in the Pacific region."

Nakasone, who won a new term last month as leader of Japan's ruling party, and Reagan had enforced an unofficial truce in unresolved U.S.-Japanese trade issues to keep them from interfering with their reelection campaigns. Japanese leaders also had been troubled by Democratic candidate Walter F. Mondale's campaign statements about protecting U.S. jobs.

India's new prime minister, Rajiv Gandhi, told Reagan he was "confident that the mutually beneficial cooperation between our peoples will be further strengthened and expanded in the years ahead."

From Manila, Philippine President Ferdinand Marcos said Reagan's victory gives "all thinking men hope that ultimately and at last we will be able to establish sanity in the world."

From South Africa, President P.W. Botha urged Reagan to "turn back the forces of international terrorism and frustrate Marxist attempts to create chaos." But presidents Daniel arap Moi of Kenya and Kenneth Kaunda of Zambia used their congratulations to urge Reagan to use his influence with South Africa to help abolish its apartheid system of racial separation.

Many of yesterday's postelection statements reflected concern over the U.S.-Soviet arms race. Australia's Labor Party foreign minister, Bill Hayden, urged that Reagan make his top priority a summit meeting with Soviet President Konstantin Chernenko. "Let the meeting be concerned with only one matter: an end to the arms race on Earth and in space and a dismantling of nuclear weapons," Hayden said.

In Bonn, Chancellor Helmut Kohl told a West German television audience, "I am sure he will use his victory to take steps that can lead to disarmament."

British Labor Party leader Neil Kinnock said that Reagan, with the strength of his reelection majority, "should use that strength to promote nuclear disarmament talks between the U.S.A. and the Soviet Union," and Swedish Prime Minister Olof Palme said, "It is most important to keep in mind President Reagan's expressed desire to seek an agreement with the Soviet Union on limitations of nuclear arms."

British Prime Minister Margaret Thatcher was less specific in her message of congratulations to Reagan, saying, "Your reelection comes at an opportune moment in international affairs when there are prospects for progress on a number of pressing questions. You can count on Britain to work closely with you in meeting the challenges which lie ahead."

From Paris, French President Francois Mitterrand told Reagan, "I am certain the friendly and confident dialogue between our two countries will develop and serve peace and progress in the world."

In Central America, U.S. allies hailed Reagan's reelection while a Salvadoran rebel radio broadcast monitored by United Press International called on "the U.S. people to prevent Mr. Reagan -- the greatest threat to world peace -- to continue occupying the White House."

In Tanzania, the crowd outside the USIS library in Dar es Salaam started forming at about 6 a.m. All through the day clusters of two or three dozen Tanzanians gathered to peer at the election returns posted inside.

"It's a very awesome thing when people speak with such a firm voice," said M.E. Massawe, a physician. "It is very impressive."

"It's a wonderful victory," said Abbas Gulamali, a Dar businessman who sported a "break dance" T-shirt, blue jeans and a Reagan-Bush campaign button he said was sent by relatives in New York. "America needed a strong leader," he said. "Carter was a nice man but he was no good. Now your dollar is strong again."

In Tel Aviv, the American Embassy threw an all-night election party at the Tel Aviv Hilton. The results of a straw poll of partygoers and anyone who stopped in to mark a ballot were announced before the U.S. television networks made their first projections. Mondale won, 163 to 121.