FOR A WHILE it looked as though the leading liberals in Prime Minister Menachem Begin's cabinet, Defense Minister Ezer Weizman and Foreign Minister Moshe Dayan, would boycott the Palestinian-autonomy talks Israel intends to open with Egypt on Friday. That embarrassment was averted by some 11th-hour bargaining that resulted in enough altering to keep the fragile cabinet consensus intact, at least for a while. But confidence in the government's position has not exactly been enhanced.

Camp David created a delicate set of interlocked obligations. Israel was not only to withdraw from Sinai but to negotiate "full autonomy" for West Bank and Gaza Palestinians, while Egypt was to normalize relations. Mr. Weizman and Mr. Dayan evidently feared that the autonomy position under preparation either would not meet Israel's obligation to negotiate in good faith or would so embarrass Anwar Sadat that he might go back on his obligation to normalize. As resolute as Mr. Sadat has been, that could yet happen. It is incredible that Mr. Begin, having won Egyptian consent to peace, could trifle with the prize.

Mr. Begin has a way of suggesting that Israel cannot fairly be criticized of stinginess an autonomy as long as no Palestinians come to the table. This is disingenuous. Playing hard to get is a familiar bargaining tactic but playing impossible to get is a tactic to block any bargaining. Mr. Begin may feel he is merely remaining true to an important part of his constituency and his ideology if no Palestinians of nationalist substance join the forthcoming talks. The Sadat government, which has been out scouting in vain, is vulnerable to a whole other set of political pressures and ideological appeals.

It is on the issue of West Bank settlements that Mr. Begin's gambling proclivities are most apparent. He is permitting and encouraging further settlement by squatters and by authorized settlers alike-it is hard to say which is the more objectionable. Mr. Begin conveys the impression that he has even more in mind than discouraging Palestinian participation in the autonomy talks. He seems to want to press Mr. Sadat to the very limits of his political tolerance, to defy him to break off the talks.

Mr. Begin is not making it easy for supporters of the Camp David process to argue to responsible Palestinians that there is something of value in it for them. In the circumstances, perhaps the best one can hope for is that the Israeli debate on autonomy will continue, under the surface if not in public view.