Jerusalem — The only salvo marking the first anniversary of President Reagan's Mideast peace initiative was the sound of Lebanese Muslim heavy artillery threatening US Marine positions in Beirut.
Only one year ago on Sept. 1, 1982, when American standing was riding high in the Mideast after the US helped engineer the evacuation of Palestine Liberation Organization forces from Beirut, the Reagan plan seemed a promising start to a regional solution of the Palestinian problem.
Today, like so many efforts and hopes for peace over this past 12 months, the Reagan plan has been swallowed in the Lebanon quagmire.
The Reagan plan aimed at facilitating a Palestinian entity on the Israeli-occupied West Bank and Gaza Strip in federation with the adjacent Hashemite Kingdom of Jordan. It collapsed when King Hussein of Jordan decided in April 1982 that he could not join peace negotiations when the PLO denied him a green light. The PLO is officially recognized by Arab states as the spokesman for the Palestinians.
Last week, President Reagan declared that his plan was ''definitely alive and available to those parties willing to sit down together and talk peace.'' He chided Israel and the Arab nations for failing to grasp the opportunities offered by his year-old Mideast peace proposals.
But informed Western sources say the Presidential reendorsement of the plan was meant primarily to forestall news media charges that he had dumped it, with no illusions that movement on the plan will be revived.
What brought the Reagan plan to its ignominious end? ''Lebanon was a big part of it,'' an informed Western analyst insists. ''There is no question that Lebanon sucked away most of the American diplomatic energy.''
The Reagan plan was issued at a time when the Lebanon question was thought to be resolvable within two or three months. On Sept. 1, 1982, pro-US Christian strongman Bashir Gemayel, a long-time secret ally of Israel, had just been elected president of Lebanon. Syria was still reeling from its military losses to Israel and had not yet strengthened its ties with the Soviet Union. Expectations were that Israel and Bashir Gemayel would soon conclude a deal on withdrawal of Israeli troops from Lebanon.
Today, well-informed Israeli and American analysts concur that the US should have concentrated on quickly resolving the Lebanon situation while Syria was still weak, before launching a regional peace initiative.
But, at the time, conditions seemed ripe for the Americans to make a bold move. With the PLO in disarray, following its expulsion from Beirut, King Hussein was seen as having maximum flexibility to join negotiations on behalf of the Palestinians.
Moreover, the US was eager to repair damage in its relations with moderate Arab states who believed the US had sanctioned the Israeli invasion of Lebanon. The US also wanted to reassure its key ally, Egypt, that the peace process for which the Egyptians had risked so much would forge ahead despite the Lebanon war.
In retrospect, the American plans probably died along with Lebanese President Bashir Gemayel when a bomb wrecked his party headquarters on Sept. 14, 1982. Israeli troops entered west Beirut almost immediately, and the Sabra-Shatila massacre of Palestinians by Christian militiamen took place two days later.
US special negotiator Philip C. Habib had promised the PLO in negotiations on their evacuation that Israeli troops would not enter Beirut and that Palestinian civilians who remained there would be protected. US credibility as a negotiator had suffered its first major blow.
A series of American miscalculations followed. Ambassador Habib put forward unrealistic target dates for the conclusion of negotiations on Lebanon. He told newly elected President Amin Gemayel that the talks would be finished by Christmas, and he predicted to King Hussein, during the King's Christmas visit to Washington, that negotiations would be wrapped up within two months.
Informed sources say Mr. Habib may have intended these target dates as a pressure on the Lebanese. But his apparent optimism seems to have deluded the US administration into false hopes. His predictions might have come true if Israel had been negotiating with the Lebanese only for a security treaty to ensure the safety of its northern settlements from attack across Lebanon's southern border.
But Israel, spurred by a determined minister of defense, Ariel Sharon, insisted on a political treaty including normalization of relations with Lebanon. General Sharon, who opposed any US involvement in Israel-Lebanese negotiations, delayed the opening of official talks from October until early January over the minor issue of the venue, while conducting secret exchanges with Lebanese Christian colleagues of the late Bashir Gemayel on terms that only Bashir - and probably not even he - would have had the strength to deliver.
By the time official negotiations started, President Amin Gemayel was already looking over his shoulder at Syrian threats against a peace treaty with Israel. And the Israelis were in no hurry to complete talks if this would facilitate progress on the Reagan plan, which they had opposed from the start because it called for return of occupied territories to the Arabs.
By January the Reagan plan had become a hostage to the Lebanon negotiations. In September and October the key condition for King Hussein's joining talks was a US commitment to halt massive Israeli Jewish settlements on the occupied West Bank, which both Arabs and Israelis viewed as a foreclosing of the possibility of return of occupied land. But as 1983 wore on, American inability to mediate an Israeli-Lebanon accord and withdrawal of Israeli troops from Lebanon became the litmus test of US credibility as a mediator in broader Mideast talks.
When the crisis between King Hussein and PLO leader Yasser Arafat came in April 1983 - and Mr. Arafat denied the King a green light to negotiate - there was still no clear evidence that US mediation could induce Israel to leave Lebanon. This fact strongly affected the King's decision not to enter the negotiating process.
American hopes for resuscitating the Reagan plan - which most observers by then had declared dead - now focused on resolving the Lebanon dilemma. But when an Israeli-Lebanese accord was finally produced in May 1983, Israeli withdrawal was made contingent on the pullback of 40,000 troops by Syria, which firmly rejected the peace-treaty-like agreement.
The US appears also to have seriously miscalculated the Syrian factor, trusting Syrian commitment to the Saudi Arabians to leave Lebanon and banking on the Saudis to pressure Syria. But while the Syrians committed themselves to the Saudis in writing to leave Lebanon simultaneously with Israel, informed Western sources say the statement was vague and gave no hint that the Syrians would accept Israeli political gains in Lebanon. Moreover, Saudi pressure never materialized.
Syria, now virtually in control of a shattered PLO, appears to have no intention of leaving Lebanon soon.
The upshot: The Reagan plan lies moribund. Israeli troops are prepared to remain indefinitely in southern and eastern Lebanon. And the US is stuck trying to shore up a faltering Lebanese government and facing the reality that a precipitous pullout of beleaguered US Marines could shred whatever US credibility remains in the Mideast.
As for reviving the Reagan plan, informed sources say the President has no intention of changing its contents or adding any sweeteners for the Arabs, such as the mention of the Golan Heights or a wider Mideast negotiating framework, which might attract Syria. Nor, they say, does he have any intention of pressuring Israel economically to halt settlement on the West Bank, unless Jordan first makes an unequivocal commitment to negotiate.
But the Jordanian monarch is holding firm. Recently he appeared angered at a confusing series of US statements on Jewish West Bank settlements which called them ''obstacles to peace'' but said their dismantlement was ''impractical.''
The only slight chance the King might stir,according to well-informed analysts, is if Israel's opposition Labor Party should take power following the resignation of Israeli Prime Minister Menachem Begin. But at this point such an event seems unlikely. A well-placed Western source says, ''I don't see next year as very productive in the Mideast peace process.''