Begin's dilemma on defense minister

Israel's controversial defense minister, Ariel Sharon, is digging in his heels against his critics. He is insisting that he will not resign, despite the recommendation of the Kahan Commission into the massacre of Palestinian refugees in Beirut, which charged him with ''personal responsibility'' for not foreseeing and preventing the carnage carried out by Israel's Lebanese Christian allies.

His aggressive campaign to drum up support from the public and within his party for his remaining in office has created a tricky political situation for Prime Minister Menachem Begin.

The Israeli Cabinet appears headed toward approving the implementation of all the recommendations of the Kahan Commission, though the Cabinet decision was put off again on Wednesday. This should mean that General Sharon would have to step down.

But the defense minister is insisting this would be a reward to Israel's adversaries, among which he prominently lists the United States. The Americans, he argues, want him out so they can force Israel to make compromises in Lebanon, and can impose on Israel a Palestinian state next door in the Israeli-occupied West Bank and Gaza Strip.

While the Kahan Commission's findings are not legally binding, and some government members believe its recommendations are far too harsh, it would be awkward for Mr. Begin to ignore them. But the prime minister has told the Cabinet that he does not want to fire Mr. Sharon, who has been his alter ego in carrying out Israeli policy in Lebanon and the occupied territory.

Mr. Begin wants to call new elections, in effect putting the Kahan Commission results to a public vote. Mr. Begin believes, and the polls bear him out, that his party would be returned with additional seats.

The opposition Labor Party, mired in internal leadership and ideological struggles, believes the same, and is keeping a low profile while the government ponders its dilemma.

But Mr. Begin needs a majority vote of parliament to call new elections. And two key coalition partners - the National Religious Party (NRP) and Tami, an ethnic party of Jews of North African origins - have so far been reluctant to support early elections because they fear they would do badly. Mr. Begin has told colleagues that he fears if he presses for new elections these coalition partners might withdraw from the government and form an alternative coalition with the opposition Labor Party.

Another way out of the crisis is being discussed intensely: a tactical resignation by Mr. Begin, as an indirect way of achieving Mr. Sharon's ouster. The resignation of a prime minister automatically means the resignation of the entire Cabinet. The key here would be to first get a written commitment from his coalition partners to regroup in a new Cabinet under Mr. Begin. In such a case, Mr. Sharon might be offered a different portfolio, which is acceptable even to Cabinet ministers who want to see him quit as defense minister.

In effect, nothing would be changed in the makeup of the reconstituted Cabinet except Mr. Sharon's job.

Whether or not all the coalition partners would sign such a pledge, and whether this plan would placate Mr. Sharon, is still not clear. Moreover, the process could take weeks, leaving the country in a state of political limbo at a time when it is beset by military problems in Lebanon and pressures from the US.

For the moment, Mr. Begin does not seem to be tending toward the tactical alternative and there are some signs that the NRP and Tami might accept early elections if there is no other choice. Sources in the NRP say they fear their voters would not forgive them if they crossed over to form a coalition with the Labor Party rather than go to the polls. If new elections become a ''must,'' both parties would prefer to see them held next November, which would give them some time to resolve their internal party difficulties. Once new elections are called Mr. Begin would head a caretaker government, none of whose members - including Mr. Sharon, if he remains in the Cabinet - could be dismissed before the vote.

Mr. Begin would prefer to let things cool down and not rush into a decision. But many members of his party are anxious that he move quickly so as not to repeat the mistake made after the Beirut massacre itself when the government lost ground at home and abroad because it reacted late.