Peace Now, the Israeli citizens' lobby, is gearing up to win over the American Jewish community to its program of opposing Israel's rule over the million-plus Arabs of the West Bank and Gaza, halting the settlements there and urging "negotiations with any Palestinian body that renounces terrorism and accepts the path of peaceful negotiations as the only way to solve the conflict."

Predictably, the effort is under challenge from those Israelis who feel that Israel cannot afford to have Jews outside Israel in dissent on vital security-related issues, and from those American Jews who believe that expressions of dissent comfort the enemy. But though it is in this aspect a parochial argument, it is at the same time more. Peace Now may deepen its influence in Israel and it may now strengthen the already evident tendency of American Jews -- who do have some influence on American policy -- to bolt from support of the Begin government; to the extent that it does, the Mideast scene will be altered.

In fact, you don't have to be Jewish to admire Peace Now. I admire it because, in an Israeli context where it is psychologically and politically very difficult to speak its sort of truth to power, Peace Now does exactly that with shining moral logic and political courage.

The Israeli-Palestinian confrontation, says writer Amos Oz, a leader of the two-year-old movement, "is a clash between total justice and total justice." He goes on: "I believe in a Zionism . . . that accepts both the spiritual implications and the political consequences of the fact that this small but precious land is the homeland of two peoples fated to live facing each other, willy-nilly, because no God nor angel will descend to judge between right and right."

Peace Now accepts, in short, that both Palestinians and Israelis have national rights that must be adjusted to each other in direct negotiations.

It is fair to say, I think, that Menachem Begin and his followers will never accept this formulation. In a real sense, he is not so much offended as sustained in his own basic philosophy by Palestinian rejection of Israel's national rights. It would be a severe political embarrassment to him if the PLO changed its spots and announced it was ready for mutual recognition.

The Labor opposition's stance is trickier. Labor is probably the natural voting home for Peace Now, a loose independent organization whose claim to be "supported" by "hundreds of thousands of Israeli citizens" has yet to be tested in an election period. But Labor looks forward less to Palestinian rights than to an agreement with Jordan that would end Israeli rule over the West Bank Palestinians and restore them to some kind of ultimate Jordanian control.

I happen to think this gives Labor bargaining possibilities that Begin cannot dream of -- or rather, possibilities that give Begin nightmares. But Labor policy remains a good distance from Peace Now, and the organization, assuming that it stays in business, would probably be a thorn in Labor's side if it returned to power.

Obviously, a single-issue movement like Peace Now can achieve a focus and purity that a broad-based political coalition cannot. That is why, realistically speaking, it is better to regard Peace Now is a growing and positive influence in Israel rather than as a likely vehicle for carrying all its ideas into national policy.

Peace Now's vigorous democratic thrust is immensely reassuring, especially coming as it does at a time when the Israeli scene is clouded by increasing official violence and unofficial Jewish as well as Arab terror on the West Bank. But Peace Now is not going to be running Israel after the next elections.

There is, however, as even more soberring aspect that ought to be taken into account by those who would either cheer on Peace Now or use it, as even some Peace Now people worry that it will be used, as a cover behind which to put a one-sided squeeze on Israel.

There is no equivalent on the Palestinian side. There are individuals, there are tendencies, there are whispers, there are third-party assurances, there are equivocations, there are retreats, there are rejections. This is what finally undermines the initiative and hinders the spirit and impact of those Israelis (and their foreign supporters) most ready to grasp the Palestinian problem in its full dimensions. It is the question for Palestinians and for their supporters, Arab, European and American.

Where is the Palestinian Peace Now?