The Reagan administration reviews its Middle East policies this week, amid signs that American credibility has declined in the region. At the same time, through a strengthening of Syria, Soviet credibility appears to have increased. Restoring US credibility would be one aim of a reinvigorated Middle East policy.
Some administration officials are proposing that the United States strengthen its ties with Israel, reverse the Israeli movement away from involvement in Lebanon, and thus gain new leverage over the Syrians. Others say realism demands an accommodation with Syrian power. But officials also want to strengthen ties with Arab nations friendly to the United States, such as Jordan and Saudi Arabia - not an easy thing to do while tightening the Israeli connection.
Whether the administration will make a new push to resolve the Palestinian issue - the stalemate over this issue appears to be one reason for the decline in American credibility - remains to be seen. Most observers consider this to be an unlikely prospect, and especially difficult to pursue in an election year.
A leading figure in the policy review scheduled for this week is Robert C. McFarlane, President Reagan's recently returned special envoy to the Middle East and the person named Monday to replace William P. Clark as the President's national security adviser.
During his three months as special envoy, Mr. McFarlane is reported to have consistently advocated strong action against Syria as a means of increasing American diplomatic leverage. He might be amenable to the idea of closer cooperation with the Israelis, with whom he seems to get along well. But some observers are convinced that, in the end, McFarlane will simply implement whatever policy is worked out by influential officials in the State and Defense Departments and by the President himself.
Joyce Starr, director of the Near East program at Georgetown University's Center for Strategic and International Studies, says McFarlane, entering the administration's decisionmaking process at midstream, is not likely to make a decisive difference in Middle East policy.
''McFarlane is known to be a disciplined implementer of policy and not a man who creates policy as he proceeds,'' said Dr. Starr. ''He's going to listen to the consensus.''
Starr, who visited Lebanon this past summer, says that the administration may be moving in the direction of accommodation with Syria, and suggests that this may be undermining the confidence of the Lebanese government of President Amin Gemayel.
''We're looking for a way out,'' says Starr. ''We're looking for a way to reduce our involvement and commitment.''
But the usually well-informed Middle East Policy Survey argues in its current issue that an alternative scenario is being worked out in the State Department which has attracted the attention of a number of senior officials.
According to the Survey, the author of this approach, Peter Rodman, a former aide to Henry Kissinger and now with the State Department's Policy Planning Council, has argued for US cooperation with Israel as a way to fill the power vacuum in Lebanon. The US, according to this thesis, should encourage Israel's efforts to work out arrangements with the mostly Shia Muslim population in southern Lebanon. Secretary of State George P. Shultz is reported to lean in favor of the Rodman proposal. But other State Department officials, as well as some Defense Department and White House officials, are reported to oppose the idea. Mr. Rodman himself declines to comment.
What seems evident is that the Soviet Union has regained some of the credibility in the Arab world which it lost in mid-1982 when the Israelis inflicted heavy losses on the Soviet-supplied Syrian forces. Armed with more sophisticated Soviet weapons, the Syrians have strengthened their role in the factional maneuvering now occurring in Lebanon and made it appear unlikely that any kind of Middle East settlement - or, for that matter, Lebanon settlement - can be reached without their participation.
Discouraged by losses, the Israelis have pulled back in Lebanon. The Syrians act as though time is on their side.
American credibility has been damaged by the failure of President Reagan's peace plan of Sept. 1, 1982, to secure any sustained movement on the Palestinian issue. The Reagan administration's failure, or unwillingess, to secure even a temporary halt to the building of new Israeli settlements on the West Bank of the Jordan River has been repeatedly criticized by Arab nations.
Arab participants in a Conference on the Search for Peace in the Middle East held recently here, and sponsored by American University and the Organization of the Islamic Conference, argued that a resolution of the Palestinian issue is still the key to peace in the Middle East.
Arab participants were unanimous in contending that what they described as unqualified American support for Israel undermines US credibility in the peace process. Many participants felt that for the US to establish itself as an honest broker in this process, it would be necessary for Israel to cease building new West Bank settlements.
Robert Neumann, a former ambassador to Saudi Arabia, argued at the same conference, meanwhile, that Syria has now emerged in a ''very powerful position.'' According to Dr. Neumann, the reequiping and modernization of Syria's air defense system by the Soviet Union is proceeding at such a speed and degree of sophistication that it will be very difficult for Syria to proceed without the USSR. Would the Soviet Union be interested in a Middle East peace initiative - even if Syria were? asked Neumann, who concluded that neither is certain.