President Carter's campaign pledge that American foreign policy would no longer "maneuver and manipulate" other countries appears to be moving closer to reality. But Carter has failed to establish that he is comfortable, confident or even in control of the uneasy passage to a post-imperial era.

Events in the Middle East and southern Africa - the two regions the Carter administration targeted for much of its early foreign policy energy and interest - have raced beyond the ability of Washington to exert control over them in recent weeks, leaving a surface impression of some disarray at the White Houe and State Department.

The administration's embarrassed hesitation in dealing with Egyptian President Anwar Sadat's dramatic initiatives in the Middle East has deepened long-standing misgivings abroad about the President's lack of the practical, high-level experience in foreign affairs, according to some American and foreign diplomatic sources.

Now, the administration confronts the possibility that those doubts could raise public questions around the world about its competence in managing foreign affairs and its ability to capitalize on sudden shifts by actors that it does not control.

Evidently concerned about the potential erosion of the administration's policymaking image, White House and State Department officials suddenly became more fortcoming this week in a series of background and on-the-record conferences that were devoted to defending the administration's handling of the Middle East and southern Africa.

Sadat this week provided the first bit of indirect criticism of the way the administration has handled the Middle East file it inherited from Henry A. Kissinger. Sadat said on American television that the United States had agreed with Israel to a negotiating framework that would have given Israel "the time they are playing for." The effect he said would have been to plunge the Middle East back into "the vicious circle" of stalemated talks about talks.

The Egyptian leader cited this as one of the chief reasons that he decided to go to Jerusalem and break the psychological stalemate. He did not go into detail on his unhappiness with Secretary of State Cyrus R. Vance's efforts to get the Geneva peace conference reconvened.

But the indirect remarks by Sadat, and more direct comments from diplomatic sources indicate that the administration's inability to influence or even get along with the new Israeli government of Prime Minister Menahem Begin and many of his most important supporters in the United States pushed Sadat into his high-risk venture.

Begin had openly defied Carter by legalizing new settlements on the Israeli-held West Bank territory and by stepping up and publicizing the Israeli military role in southern Lebanon.

The secrecy that enveloped the joing Soviet-American declaration on the Middle East cut out, and evidently upset, career diplomats and Capitol Hill politicians and staffers who might have otherwise helped defuse some of the uproar from the American Jewish community.

The last straw evidently came in October, when Vance had to withdraw prior assurances to Sadat that Israel would consider changes in the terms of the Israeli-American working paper that was supposed to clear the way for the Geneva talks. Israel now refused to budge. Sadat was told, and the Egyptian president moved to take matters into his own hands.

The face-to-face meeting between Sadat and Begin has been praised by Carter and in the diplomatic community here and abroad. The low American profile would seem to fit neatly with Carter's call in a Chicago speech in March, 1976, for an end to a foreign policy "that has consisted almost entirely of maneuver and manipulation" of others.

But the resulting scramble by Washington to catch up with developments in the Middle East has not been carried out with enough skill or grace to retain the confidence of all onlookers.

"Do they really know what is going on out there?" one Arab diplomat normally sympathetic to American policy in the Middle East asked as the White House delayed its response to Sadat's invitation to a preparatory Cairo conference. "Sadat needs every bit of support he can get, and quick."

"This administration did not move to capitalize on this in the was Kissinger would have done," said a senior American diplomat now posted abroad. "Even if he had been flabber-gasted. Kissinger would have played it as if it had been part of his strategy all along, and would have bargained off his support for it for something."

The rapid changes in the Middle East come as the administrations faces a major test of its ability to keep a completely united front with Britain in the effort to reach a settlement to Rhodesia's constitutional crisis and guerrilla war.

Prime Minister Ian Smith staged a smaller version of the Sadat sudden reversal last week by offering to negotiate with African politicians about universal suffrage for the black majority in the country.

The United States continues to emphasize that any deal that is not acceptable to the so-called Frontline States that support the guerrillas will not end the war, but Britain showed itself to be slightly less negative about Smith's offer. The gap in positions is miniscale, but it is also the first one to appear since Britain and the United States began to promote their joint settlement plan actively.

In Western Europe, apprehension on Carter's approach to some key foreign policy issues, such as nuclear exports and arms transfers, appears to have abated as Bonn and Paris have concluded that Carter is not a "zealot" on these or other issues.

But deep concerns about Washington's handling of strategic arms limitation talks and mutual force reduction persist. They broke into public four weeks ago in speech given at London's Institute for Strategic Studies by West German Chancellor Holmut Schmidt.

Schmidt called in the speech, which is being studied closely by U.S. officials, for stringent examination by Western European of Amercian attitudes toward cruise missiles, the neutron bomb and all proposals being put forward in the separate sets of arms negotiations being conducted by the superpowers.