The dramatic peace initiative that began with Egyptian President Anwar Sadat's visit here last November is now deadlocked and there is every indication that the historic chance for peace is, in the warning words of British Foreign Secretary David owen, "spilling away into the sand."

This is happening despite the fact that both sides may want and need peace. The recent letter to Prime Minister Menachem Begin from Sadat, although it contained no new positions, was at least an indication that Sadat wants the negotiations to continue.

Sadat's November visit did achieve a psychological breakthrough in that it disproved the long-held Israeli theory that no Arab state was willing to make a real peace with Israel. But it is now clear that the initiative is not likely to bear fruit unless Begin can grasp the new situation and make his own psychological breakthrough.

At the moment, Begin is torn between one set of advisers who say that entirely new concepts of security and territory must be devised in response to the Sadat initiative and those of his own right wing who are keeping him tied to the old mold in which his political life was formed over 30 years.

For 10 years, Israelis have said that their real interest was security not the occupied territories. Perhaps this was true in 1967, but it may no longer be true. The recent Israeli interpretation that U.N. Resolution 242 does not require Israel to withdraw from the indicacupied West Bank and Gaza is an indication that Begin may want peace but he wants the occupied West Bank and Gaza too.

Begin has the power to lead the people of Israel in either direction toward the compromise that the Sadat initiative has engendered, or back into the paranoia and fear that can be justified in terms of Israel's past isolation but will not bring peace.

In recent weeks, Begin has been taking the latter course. He has been making speeches that play on the deepest fears of this Jewish country that has been through so much. Begin's rhetoric is as powerful as ever. When Begin was in London, British Secretary Owen complained that Begin lectured to him rather than conversed with him. The posture Begin is assuming tends to build up again the psychological barriers that Sadat had hoped to break down.

It is unlikely that Israel would throw out the Begin government if it misses the chance for peace, but the rising criticism of Begin in the press and even among members of his own coalition is unprecedented since he came to power.

There is enough blame on both sides to explain the present impasse. Sadat's premature withdrawal of his delegation from the political talks in Jerusalem showed a misunderstanding of what can be expected of the Israeli decision-making process.

But it is indicative that Sadat, in his speech before the Israeli parliament, admitted that the Arabs had made grave mistakes in dealing with Israel and he called upon both sides to open a new chapter. No one has heard Begin admit that Israel has ever made mistakes in its dealings with the Arabs, and it may be that Begin's attitudes have have become too hardened over the years to change.

It is said that Sadat tried to determine before he came to Jerusalem whether Begin was a strong leader who could make the necessary break with the past for peace. There was every indication, at first, that Begin was just such a strong leader but even this image has begun to fade.

The entire issue of the settlements --deceive by promising not to make new settlements but allowing settlers onto the West Bank in the guise of archeologists -- is, in the words of former director general of the Foreign Office Shlomo Avineri, "multiple lying . . . much more reminiscent of the behavior of a fearful diaspora leadership than that of an independent state."

The United States shares some of the blame by encouraging the Israelis to believe that putting civilian settlements within army camps on the West Bank would be acceptable. But the ill-disguised infighting on the settlements issue within the Israeli cabinet enforces the image of a confused leadership.

Begin has been unable to lead his own right-wing faction in the direction he proposes. Concessions to the right explain why his proposals for settlements in the Sinai, as well as self-rule on the West Bank, toughened from the time he showed them to President Carter to the time he presented them to Sadat.

Next week Begin is to meet with President Carter in Washington in an atmosphere that will be close to confrontation. No minor concession, such as a promise to go slow on settlements in the occupied territories, is likely to paper over the differences between the United States and Israel.

Not the least of the problems will be Israel's latest contention that U.N. Resolution 242 does not include a commitment to withdrawal in the West Bank and Gaza. The vagueness of 242 was at the same time its strength. The resolution, passed in 1967, calls for Israeli withdrawal from territories but does specify what degree of withdrawal nor does it specify where the withdrawal should occur. Now Israel is contending that it may interpret 242 as not requiring withdrawal from the West Bank and Gaza strip.

But the previous Labor Day government gave every indication in 1970 that Israel would consider 242 as calling for a withdrawal from the West Bank and this was passed to Jordan in a memorandum via the United Nations. It was adopted by the Cabinet and approved by the parliament. Begin, then a member of the coalition government, resigned in protest because, as he then explained, he was opposed to committing Israel to territorial concessions on the West Bank.

It is no surprise that Begin and his Likud Party oppose concessions on the West Bank. It was a plank of their platform. But Begin did not inform his allies that he was altering the accepted meaning of 242 when he came to power last June and to do so now is seen as a step backward in the peace process.

Former Foreign Minister Abba Eban wrote recently that "the question whether [the Begin government] can act with cavalier indifference to the commitments of its predecessors deserves a passing reflection . . . The fact that the Likud Party obtained 39 percent of the election votes does not constitute a national endorsement for the principle of no foreign rule west of the Jordan."

The Foreign Office is trying to smooth over the issue by saying that Foreign Minister Moshe Dayan is on the record as saying that the government will seriously consider a territorial division of the West Bank if the Arabs submit such a proposal but that Israel does not want to commit itself in advance when there is no negotiating partner for the West Bank.

Begin has always maintained that all of what was once British Palestine should remain under Israeli control and his plan for limited self-rule on the West Bank and in Gaza is a method of keeping the present occupation under a different guise. No Arab state, not even the most moderate, is likely to accept this.

The question of what to do with the West Bank and Gaza goes far beyond wrecking the Sadat initiative for a comprehensive peace -- which probably will be the short-term result of the Begin government's policies; they are not changed.

The continued Israeli occupation of the land of a million unhappy Arabs, with one of the highest birth rates in the world could mean, as Deputy Prime Minister Yigael Yadin once predicted, that Israel can continue to remain a Jewish state but not a democratic state.