The American Jewish community once used to give full and automatic support to any action by the Israeli government be it right or left. Jewish lobbying groups fought - often with success - to end the career of any American politician seen as hostile to Israel's interests.
But when Madeleine Albright, the US Secretary of State, visited Israel earlier this month, 40 leading American Jews wrote her an open letter saying she should not focus solely on Israel's security and allow "the latest terrorist atrocity [to be used] as a pretext to destroy the Oslo process".
Given that Benjamin Netanyahu, the Israeli Prime Minister, and his government were looking for just such a pretext, it angrily denounced the letter as a stab in the back. Danny Naveh, the cabinet secretary, referred to those who had signed the letter as "marginal Jews."
Mr Netanyahu, who made his career in the 1980s as a diplomat in the US, has always counted on the Jewish lobby to stop President Bill Clinton taking any initiative he dislikes. Now American Jewish leaders were reported to be telling officials in the White House that if they were tough with Israel they need not fear a backlash from Jewish voters.
Any sign of a schism opening up within the six million-strong American Jewish community, with its immense political power, is examined with intense interest by Israelis. With the end of the Cold War the country is no longer the strategic asset it once was to the US. Israel's influence is more than ever dependent on the world's perception of its political strength in Washington.
Under President Clinton, this has reached an all-time high. When he entered the White House in 1992, some 85 per cent of American Jews voted for him and just 10 per cent for George Bush. Though they are just three per cent of the population, JJ Goldberg says in "Jewish Power", a study of Jewish politics in the US, that American Jews provide "between one fourth and one half of Democratic campaign funds".
Polls show that a majority of US Jews have supported the Oslo peace talks with the Palestinians. But the Jewish lobbying organisations have increasingly come under the control of the militant right, always suspicious of any deal with Yasser Arafat, the Palestinian leader.
The control of the militant Zionists, for whom Israel is always in danger of annihilation, reflects a real division within American Judaism. The politically moderate may be the majority. But they are also the least engaged with organised Jewish life. By one rough estimate, some four million American Jews are largely assimilated, often marrying non-Jews, but a further 1.5 million are moving in the opposite direction, becoming more exclusively Jewish.
Not surprisingly, it is the latter who are most prepared to invest time and money in lobbying groups. For instance, Dr Irving Moskowitz, a multi- millionaire from Miami Beach, not only financed a new settlement in Ras al-Amoud in Jerusalem, but gave more than $500,000 (pounds 316,000) to the Zionist Organisation of America, an extreme group of the right, which sees opponents of Israel lurking in the pages of the New York Times.
It is not merely that the Jewish community has achieved veto power on White House policy over anything to do with Israel. Mr Netanyahu's sympathies are with the Republicans and he can look to support from Newt Gingrich, the Speaker of the House, and Trent Lott, the majority leader in the Senate.
In the past, the Israeli Labour Party has always hoped that pressure from the US would moderate the policies of their own government. They have usually been disappointed, though in 1991 President Bush refused to give Israel a $10bn (pounds 6.4bn) housing loan guarantee while settlement went on in the West Bank. President Clinton, on the contrary, refused to condemn the building of Jewish settlement at Har Homa in Jerusalem this year which led to the present stalemate in negotiations.
But there is a reason for taking the present signs of dissent more seriously. Most American Jews belong to Reform or Conservative synagogues, both secular traditions in Judaism, while Israel is almost entirely Orthodox. Discrimination by the Orthodox Rabbinate against the small Reform congregations in Israel causes maximum offense in the US, because it implies that American Jews are not sufficiently Jewish.
There is one other weakness in the stance of the main Jewish lobbies. It is unrelentingly negative. "You can always rally people against," admits Malcolm Hoenlein, director of the Conference of Presidents of Major American Jewish Organisations. "It's very hard to rally people for." This, in turn, presupposes no solution to the Israeli-Palestinian conflict except total victory for Israel. This endless battle may be good for lobbies, but less so for the Israelis and Palestinians who have to fight it.