Jerusalem — While the situation in Lebanon enters the critical stage, Israel is functioning without any clear leadership. Prime Minister Menachem Begin, who announced his intention to resign more than two weeks ago, remains secluded and apparently physically incapable of presenting his formal resignation to the Israeli President.
Policy on Lebanon is being made without him, and former Defense Minister Ariel Sharon has been voicing ugly criticism of government policy in a way which he probably would have never dared were Mr. Begin still in charge.
Begin's delay is raising legal questions about the time lapse between his announcement and his formal resignation. So long as he holds back, Israeli President Chaim Herzog is unable to ask a new candidate to form a government.
This most probably will be Foreign Minister Yitzhak Shamir, who was just chosen to replace Begin as head of the Herut Party, and who on Monday received guarantees from the 64 members of the current coalition (out of a 120-seat parliament) that they will support him as prime minister.
But as the government continues in limbo, two small coalition partners have been conducting secret meetings with members of the opposition Labor Party, creating some doubts about how easily Mr. Shamir will in the end be able to form a new government.
Legally, Begin - who has remained out of public view for the past week - could submit his formal written resignation to the President by messenger. His aides said he is loath to do this because it would lack dignity. But Attorney General Yitzhak Zamir has issued an opinion that the limits of a ''reasonable'' delay in Begin's case would be ''about two weeks.'' This was seen to imply that delaying much longer could invalidate Begin's announcement of 17 days ago.
Originally, Mr. Begin's hesitation was attributed to the desire to give his successor, Mr. Shamir, time to win coalition support. But with a coalition accord in hand, speculation is mounting - though it is firmly denied by Begin's aides - that the premier is too ill to formalize his departure.
The lack of authority at the top is affecting policy on Lebanon at a critical juncture. The daily newspaper Maariv, close to the Begin government, charged that the leader's failure to resign was preventing the ''plotting of a clear policy appropriate to the new situation in Lebanon.''
Having pulled back its soldiers from central Lebanon, where fighting then broke out between Christians and members of the Druze Islamic sect, Israel appears uncertain about how best to reassert its influence there.
Defense Minister Moshe Arens has changed the policy of his predecessor, Ariel Sharon, of placing full support behind the Christians, and is trying also to influence the Druzes.
Touring the new Israeli lines on Tuesday, Mr. Arens responded to queries about how Israel would stop Palestine Liberation Organization forces from reinfiltrating and staying in the Beirut region by insisting that Israel was ''demanding'' that the Druzes ''prevent terrorists (PLO) from drawing close to Israeli lines.''
So far, however, Arens and the Israeli military establishment appear determined not to be drawn again into large-scale involvement north of the new line at the Awali River.
An aide to Arens denied press reports that Israel had supplied any arms to the Druzes.
Arens's policies have aroused vicious criticism from former Defense Minister Sharon. Mr. Sharon seemed eager to take advantage of the Lebanon situation - and Begin's demise - to start a comeback bid from the disgrace he suffered after the Kahan Commission, investigating the massacre a year ago of Palestinian refugees in Beirut, recommended that he be sacked.
Sharon, who was accused by the Kahan Commission of not taking sufficient precautions to prevent the Sabra-Shatila massacre by Christian militiamen urged the Israeli Cabinet to sanction the use of force north of the Awali in order to avoid a massacre of thousands of Christians besieged in the Shouf village of Deir al Qamar.
Israeli officials have been extremely concerned at reports of massacres in the Shouf and have strongly implied that their private pressure on the Druzes prevented an attack on Deir al Qamar. Thus, Sharon's remarks were taken as an attempt to indirectly criticize Arens and vindicate himself.
Arens responded dryly to Sharon's statements, suggesting that the former defense minister was simply unhappy that he no longer held the office. ''This is a human weakness,'' said Arens. ''He (Sharon) must be understood. There is no need to become angry or excited.''