Beirut — With the exception of Lebanon - and then only Beirut - the Arab world today is feeling great disenchantment with both Moscow and Washington.
This falling out can be traced back to Israel's invasion of Lebanon last summer and to the continued American and Soviet ambivalence toward Iraq in its 26-month-old war with Iran. Although Moscow's standing has suffered most, diplomats and political scientists say the US, too, has lost prestige.
Moscow's reticence to step in last summer and deter Israel from working its will in Lebanon was a major failure of Soviet Mideast diplomacy. Syria, Libya, and the Palestine Liberation Organization (PLO) in particular were upset by the lukewarm Soviet reaction.
At the same time, the US suffered by association with Israel in that war, especially in the eyes of traditionally friendly countries such as Egypt, Saudi Arabia, and the Gulf states. In these countries, diplomats report, there was a perception of American complicity in Israel's invasion. Now there is a feeling that Washington is not keeping enough pressure on Israel to ease its ever-tightening grip on the West Bank and Gaza.
The most surprising of Moscow's critics these days is Libya. Its leader, Col. Muammar Qaddafi, has expressed displeasure at the Soviet Union for not actively aiding Syria and the PLO last summer. The pro-Libyan magazine Al Kifah Al Arabi last week complained that when Arabs called for help, the Soviets ''vanished behind thick walls of ice.''
Iraq, too, is critical of Moscow, but for different reasons. President Saddam Hussein last week accused both the US and the USSR of wishing to prolong the Gulf war in order to weaken the Arabs. He singled out Moscow, however, for aiding Iran, saying he has proof that Soviet weapons are going to Tehran.
Two Soviet allies, Syria and the PLO, today are looking more to the West, diplomats note. US envoys Philip Habib and Morris Draper have done much to break the chill in US-Syrian relations in their frequent visits to Damascus - though there is far to go.
''There has been a definite thaw with Damascus,'' a diplomat says. ''They are willing to listen to what the Americans have to say. But that doesn't stop their denunciations of the United States in the media.''
US gains with the PLO are only marginal. They are limited, of course, because of US nonrecognition of the organization. PLO leaders have expressed a great deal of bitterness at the US for failing to guarantee the safety of Palestinians in Beirut's refugee camps. But PLO leader Yasser Arafat has been indicating a willingness to deal exclusively with Washington if the US can deliver what the PLO wants: an independent Palestinian state in the West Bank and Gaza Strip.
American diplomats are nevertheless concerned that the US may be losing ground among its Arab allies. Says one:
''The war in Lebanon may get the credit for changing the political situation in the Middle East, or at any rate in Lebanon. But at what price? All summer long America was coming in for heavy criticism in Cairo and Riyadh.''
The war, he points out, prompted Egypt to freeze the Camp David ''normalization'' process and recall its ambassador from Tel Aviv - jeopardizing Washington's most important breakthrough in Arab-Israeli peacemaking.
In response to these less-than-satisfying policies in Washington and Moscow, many Arab states are pursuing a path of reconciliation with each other and self-reliance.
The six-nation Gulf Cooperation Council is meeting in Bahrain this week to discuss further economic integration and collective security. Kuwait, meanwhile, recently succeeded in bringing together South Yemen with Oman and Saudi Arabia to talk detente - a development that should significantly ease tension (and perhaps Soviet influence) at the southern ends of the Gulf and Red Sea.
At the same time, Egypt is campaigning hard to rejoin the Arab camp after the ostracism of the Camp David period. Arabs are coming to recognize that this is necessary. Even PLO leaders are predicting that Egypt will soon be let back in. PLO intelligence chief Abu Zaim last month made such a prediction.
Only in Lebanon does one of the superpowers - the US - feel a fresh burst of welcome. But, says a diplomat here, this is ''only in a sliver of Lebanon the size of your fingertip: Beirut.''