After reading US polls, foreign leaders scramble to get on Reagan's good side

World leaders and their Washington embassies read the American polls. So it's not surprising that many of them are already jockeying for position on the White House attention list.

From Moscow to the Mideast to Central America, contending parties are beginning to launch strategies essentially put on hold when the American campaign preempted presidential attention and brought on the usual caution about dealing with contentious issues.

As one Western diplomat observed privately this week: ''During the election season, official Washington is like the Great Bustard, which is both blinded and deafened by its own feathers during the mating season. But now the end is in sight and people are beginning to jockey for visibility.''

No major foreign capital will count the election over till it's held. Advisers remind foreign ministers and prime ministers about recent American elections, in which large leads in the polls have evaporated in the final weeks. But those same advisers also realize that if the Reagan lead holds, foreign policy matters will not have to await a change of administration in mid-January. Hence the current jockeying.

With Soviet Foreign Minister Andrei Gromyko hardly gone after his exploration of post-election possibilities, Israeli and Arab leaders are pushing forward their plans - some but not all aimed at Washington's ear.

And maneuvering by Nicaragua and its Central American neighbors has caught the United States flat-footed - and therefore gotten its attention.

First the Mideast.

For months the moderate Arabs have been trying to get together to strengthen their role within the Arab world. They are also trying to create a united front in order to press Washington to press Israel for serious action on the Palestinian problem.

Since the end of the post-election stalemate in Israel, the new Israeli government has been preparing moves on its budget and on Arab relations designed to keep Washington in its corner - both as subsidizer and as ally in negotiations with its neighbors.

Recently these Arab and Israeli moves toward negotiation have advanced a step and retreated a step.

On the moderate Arab unity front, Jordan's King Hussein has made his peace with Egypt. He did so just before receiving in short order both Palestinian leader Yasser Arafat and US Assistant Secretary of State Richard Murphy. Mr. Arafat, weakened by expulsion of his forces from Lebanon, quickly endorsed Amman's olive branch to Cairo as helpful to his cause. He called for the Arab states to reembrace Egypt, spurned since the late President Anwar Sadat's 1979 treaty with Israel.

Hussein's move is expected to serve as an ice-breaker for Iraq, which is believed to be ready to resume relations with Egypt. Cairo has given staunch support to Baghdad in the latter's long war with Iran. And Iraq is apparently ready to reciprocate.

Jordan has also supported Iraq. And Iraq is about to build a pipeline through Jordan to reach the Gulf of Aqaba, within sight of the Israeli port of Eilat. Oil is further cementing moderates Iraq and Saudi Arabia. The contract for another pipeline to carry Iraqi crude across Saudi Arabia to Yanbu on the Red Sea was granted to a French-Italian group this week.

And Saudi Arabia took its own cautious step toward Cairo when Saudi Oil Minister Sheikh Ahmad Zaki Yamani visited President Hosni Mubarak on Wednesday.

Then came the steps backward.

King Hussein spurned an Israeli overture to begin talks. Those who know his position well say he felt he had no alternative. With pressure from Syria to his north and from restless Palestinians in his own country, he cannot afford to bargain from weakness.

Washington has neglected its own 1981 Reagan plan for an Arab-Israeli solution, and weakened its longstanding support for UN Resolution 242, which defines an Arab-Israeli settlement. Hussein is not likely to talk to Israel unless he can regain full US backing for those plans. And he feels he won't get that backing until the Arab moderates unify to press Washington.

Next, progress on an Israeli withdrawal from southern Lebanon marched forward and then backward. Israeli Defense Minister Yitzhak Rabin is interested in removing his forces - to save both money and lives. United Nations Undersecretary-General Brian Urquhart had designed a plan last spring to replace Israeli troops with an expanded UN force. The aim: to keep peace in Lebanon and protect Israel's northern border. The Urquhart plan was put on hold for the Israeli elections last July. It was revived in September. But Syria and Israel still do not agree on details. And there is division in the Israeli Cabinet over how far to go on withdrawal.

Israel needs to paint a rosy picture of its diligence on both budget and peace before Prime Minister Shimon Peres's summit sessions in Washington on Oct. 8. In order to win a massive boost in US aid, Mr. Peres needs to arrive with an austerity budget in hand. To have continued US backing on the Palestinian and Lebanon questions, Peres will profit from being able to say he has tried to negotiate on both Jordan and Lebanon.

Meanwhile, efforts to bring about a negotiated solution to the US confrontation with Nicaragua also took a step forward and a step backward in recent days. The bigger neighbors immediately bordering the Central American fighting zone, the so-called Contadora group, won Nicaraguan agreement to a plan for reducing friction in and between Nicaragua, El Salvador, Honduras, and Costa Rica.

However, they immediately lost the somewhat vague US backing that their effort had previously enjoyed. The US announced it felt the plan was not specific enough to guarantee free elections in Nicaragua. This left Contadora architects like Mexico angry. But all parties went back to bargaining, with the Nicaraguan elections only a month off.

Another mediation effort, by the Socialist International meeting in Rio de Janeiro, also failed at the last minute to win an agreement between the leftist Nicaraguan junta and its leading coalition opponent, Arturo Cruz Porras. Without Mr. Cruz as a candidate, Nicaragua's election on Nov. 6 will not meet the US definition of free and open balloting.