Menachem Begin chose to go gently into the cold night, with neither a bang nor a whimper, but shrieking silence. After a visible decline in Begin's disposition over the past few months, he has chosen to spend the recent weeks unshaven, barely eating and confined most of the time to his home, so as to make his exit from history on tiptoe.

No one can say for certain just what led Begin to step down at this particular time. His only words of explanation to his friends ("I cannot carry on anymore") amounted to a confession that he had somehow failed and was no longer capable of coping with the consequences.

His longstanding and ever-faithful secretary, Yonah Klimavotsky, shed some light on the nature of this failure last week with the disclosure that Begin had resigned because of "heartbreak," stemming from four causes: the many casualties in the war in Lebanon. His erstwhile belief that the war would be brief: "He thought we'd be in and out of there in no time." His disappointment with those who had betrayed him after he had given them his trust. And, finally, his "sobering up from illusions."

This candid appraisal from so close a source confirms the premise that after 15 months of war, with 520 killed and 3,300 wounded, Begin himself is disillusioned. It is a disillusionment shared by most of his ministers and senior officers, who now hold that the war was a "do-it-yourself" fatal mistake.

There is no longer any doubt that the masterminds of this war, former defense minister Ariel Sharon and former chief of staff Raphael Eitan, whom Begin trusted implicitly, proved to be a poor excuse for statesmen. Sharon and Eitan embroiled Israel in Lebanon without really knowing or understanding the historical background of the 300-year-old Lebanese conflict, without grasping the Lebanese way of doing things--everyone doublecrossing everyone else--and, most important, without realizing that the "problem of terrorism," which they wanted to eradicate once and for all, is not military but political. Israel did not stand a chance of building a new Lebanon or of solving the Palestinian problem with bayonets.

The entire government, and very belatedly, Begin himself, eventually realized that they had been misled. As far as the Israeli viewer was concerned, the complacent grin of Yasser Arafat as he faced the television cameras in Tripoli, Lebanon--where he had returned after being deported from there "for good"--symbolized an ironic finale. The house of cards had tumbled over.

At first glance, the shattered illusions of Lebanon seem to have had an even stronger effect on Begin than on his supporters. If, in fact, it was "heartbreak" that made him resign, there are no signs as yet that the nation is as heartbroken as its leader, to the point of altering its mood and inclinations. True, there does appear to be a certain feeling in the air that "things didn't work out the way they should have" in Lebanon, but the silent majority settles for the explanations of zealous soapbox orators who allege that whatever went wrong with the war was not due to any basic misconception but to the irresponsible and unpatriotic criticism of the media and the opposition.

Begin's resignation, then, does not spell any immediate shift in popular support for the Likud government or its views. Once the Yitzhak Shamir government gets down to business, defense minister Moshe Arens will probably succeed in persuading it to end the Israeli involvement in Lebanon with as little damage as possible to its image--leaving the United States holding the bag. But Shamir and Arens are apt to make perfect bedfellows when it comes to their policy of non-concessions and their firm hand vis Ma vis the West Bank. It is a policy that rests not only on their unmitigated ideological backing of the "greater Eretz Israel," but also on the urge to parry Sharon's lunges from the right. There is a growing feeling that Sharon, ostensibly just trying to clear himself from responsibility for the massacres in Sabra and Shatila, has actually begun his relentless climb toward the prime ministership. This time- bomb is one of the new government's toughest hand-me-downs from the Begin period, and the only way that Shamir and Arens can fight him is by proving that they are more Beginistic than Begin. The new government will, for the time being, carry on with Beginism without Begin.

If Begin's resignation does not spell political unheaval in Israel at this time, it is too soon to tell how deep an imprint it will make. After all, for better or for worse, the country is losing its last authoritarian leader from the generation of the founding fathers. As Begin steps down there remains a void, and most of the people stand to lose the feeling that "someone is up there--someone fatherly and reliable, imbued with a deep sense of history and a keen feeling for danger, someone who can be trusted, someone who makes you feel secure. From now on, Israelis are going to have to compromise on more mediocre leaders. They will have to compromise on less far-reaching ambitions. They will have to compromise on dealing with problems that cannot be resolved by military force. When all is said and done, they might just learn that the only way open to them at this stage is to compromise with their Arab neighbors.

In the longer run, Begin's resignation might just turn out to have been a turning point in the history of Israel.