Mideast: does US care?

When will the United States abandon its still passive peacemaking role in the Middle East? Washington understandably did not want to rock the boat while the Israeli pullback from Sinai was in process. But with that portion of the Camp David accords accomplished - and, it must be said, with dignity and skill on Israel's part for all the last-ditch resistance of Jewish zealots - is the US prepared to reassert itself in the search for a comprehensive peace?

In general the Reagan administration has recently been conspicuous for its lassitude on the issue. Why, for instance, is there so little reaction in Washington to Israeli statements and acts that are prejudicial to peace and to the US national interest?

Menachem Begin has just performed perhaps the noblest act of his turbulent career as a fervid Zionist. He has turned back to Egypt all the land seized in war. Yet in the wake of this momentous event the world is again hearing words from Mr. Begin which stand international law on its head. He told an American television audience this week that there was no need to annex the West Bank since it already belonged to Israel. This echoed a similar statement last month in which he used the biblical terms for the West Bank:

''Judea and Samaria are occupied territory? Judea and Samaria were occupied territory by the Jordanians, who conquered the western part of the land of Israel. And once it was occupied territory by the Egyptians when they invaded Israel. But it is not occupied territory now. It is the land of Israel.''

This does not represent a departure from Mr. Begin's consistent position down through the years. He is certainly entitled to it. But should the United States benignly let him hold court in this way by not challenging a flagrant reinterpretation of international law? UN Resolution 242 of 1967 calls for Israel's withdrawal from ''occupied territories,'' which included Sinai, West Bank, the Gaza Strip, and Golan Heights. The prime minister's flat assertion that the West Bank ''is not occupied territory'' means that he believes the terms of 242 have been fulfilled with Israel's withdrawal from Sinai and do not apply to other disputed lands. He does not intend, in other words, to withdraw further.

Presumably the US does not agree with this position. Yet it is not clear where the present administration stands. Surely this is a time for the US to reaffirm the view it has long held: namely, that 242 calls for Israeli withdrawal from territory on all fronts - the Golan Heights, West Bank, and Gaza as well as Sinai - and that such withdrawal is to take place under peace treaties giving Israel ''secure and recognized boundaries.'' Such a reaffirmation is all the more needed as Jewish settlers take over more and more land in the West Bank and as the Palestinian Arabs' political institutions are being destroyed. There should be no mistaking in Israeli minds that the US disapproves these moves - on moral and legal grounds. Yet the impression conveyed now is that Mr. Begin is rewarded for opposing US policies.

Nor need the US be any less reticent where the Arabs are concerned. Mr. Begin has a creditable case when he refuses to deal with a Palestinian organization which remains formally committed to Israel's destruction. There is little doubt the Mideast diplomatic logjam would once again be broken if the PLO had the good sense to revoke the offensive parts of its convenant and declare - and mean - its recognition of Israel's right to exist. Refusal to do so strengthens Israel's hand. Indeed the Arabs ought to reflect on the opportunities lost in the past to make peace and on the consequences of their own shortsightedness. Why should the US not press them on this score?

The Middle East demands attention, the Falklands notwithstanding. The US ostensibly remains committed to pursuing autonomy for the Palestinian people. But its strange silence, especially in the face of provocative Begin policies, raises doubts about how deep that commitment is. Many fear that Palestinian frustration will lead to more violence and a full-scale war in Lebanon.

The question is whether Washington intends to play an active part in achieving an Arab-Israeli peace - or simply continue running around putting out fires.