THE OUTLINES of the Reagan administration's Middle East policy are considerably more in view after Mr. Begin's visit. Though there is no evidence that anyone planned it that way, the centerpiece is turning out to be the massive air defense package that goes under the name of AWACS. More than any other single element, it typifies what the administration is trying to do.

The Saudis evidently asked for AWACS not so much to prepare for either a Soviet or an Israeli attack, although both contingencies continually bob up and down in their minds, as to test the strength of their American connection. The Saudis, to test that connection, might have asked the administration to make an all-out political assault on the Palestinian question. But they did not. It would be interesting to know if deep down the Saudis feel they have made the right choice or for that matter whether they realize fully that, in American eyes at least, they have chosen.

For the United States plainly intends to use the AWACS sale not simply to prove its fidelity to the Saudi royal family and to assuage its assorted military jitters. The Begin visit has added to the impression that the United States also intends to use AWACS as a subtle surrogate for up-front action on the Palestinian question. In a sense, Israeli resistance to AWACS is gold for the administration's Saudi policy. What better way, than by standing up to "Zionist" pressures, can Washington show Riyadh that the American heart is in the right place. In deed if not in word, AWACS commits Saudi Arabia to the American "strategic consensus" that it hesitates to join openly. Having asked the administration to go toe to toe with Israel on AWACS, how can Saudi Arabia avoid a reciprocal obligation when the administration steps up to the line? That reciprocal obligation is to put the Palestinian question off a bit longer.

The Israelis, too, are finding a certain value in AWACS. This refers not merely to the compensation Israel appears to be receiving in military aid and, beyond that, in a more formal and open approach to the military-strategic cooperation that has always been a useful part of U.S.-Israeli relations. The administration does not wish to make so much of this new cooperation as to unnerve its Arab friends, but it is willing to make as much of it as it needs in order to impress the Soviet Union and its clients. Behind its hand the administration says to those anxious Arabs just what it says in public to anxious Israelis: the more Washington expands its military presence in the region, the better able it will be to exercise a restraining influence on those parties, Arab or Israeli, that it ostensibly supports.

At the same time, moreover, the administration is offering Israel, by way of further compensation for selling AWACS to the Saudis, a go-slow policy on the Palestinian issue. The substance of Palestinian autonomy negotiations was "not raised" between himself and President Reagan, Mr. Begin reported on "Meet the Press" yesterday. Apparently the administration is going along with Mr. Begin's insistence that he and President Sadat of Egypt be left to work on Palestinian autonomy alone. This may spare President Reagan some of the taint of a washout of the autonomy talks. It also ensures there will be no strong American input into a negotiation in which American interests are deeply involved.

All of this unfolds predictably from positions on the Middle East that Mr. Reagan enunciated during the campaign. Some differences remain visible within his administration: Secretary of Defense Weinberger, for instance, seems to believe there is political value in confronting Mr. Begin at least semi-publicly on his more controversial policies, while Secretary of State Haig thinks that a manner of discretion gives the United States better cards. But the main line of policy seems set.

Believing as we do that a direct and serious approach toPalestinean-Israeli coexistence is critical, we have misgivings about the Reagan course. The notion that Mr. Begin, having pocketed some major political and security gains in his trip to Washington, will turn around and do his part to make the autonomy talks come alive takes a long leap of faith. But it has to be conceded that the PLO has played straight into his hands. Characteristically, terrorists chose Saturday, while Mr. Begin was still in Washington, to kill and wound more innocents--this time, as it happened, Italian pilgrims--in Jerusalem. The PLO itself clings to its charter's outrageous stated intent to destroy Israel. Mr. Reagan apparently hopes that playing hard to get, in the Middle East as elsewhere, will eventually pay dividends. His policy is a triumph of hardware over foresight, a real gamble.