It's a question at least as old as the Jewish state: how should Diaspora Jews talk about Israel? The argument is still often made that Diaspora Jews owe support to Israel and have no right to engage in criticism of a country they do not live in.

But in the last few years this argument has been increasingly challenged. Even the Jewish Agency recognises that Diaspora Jews need a space in which to talk openly about Israel, and its Makom project (a joint partnership with Haaretz.com) encourages meaningful engagement with Israel rather than simply uncritical support.

On Monday, a discussion organized by the Jewish Community Center for London entitled "Can We Talk about Israel?" illustrates just how much the Diaspora debate on Israel has changed.

All the panellists were of the left, all opposed the occupation, all were horrified by Avigdor Lieberman and all agreed that it was important to talk about Israel critically rather than give it unqualified support.

Yet there were still massive differences between the panelists: Guardian and Jewish Chronicle columnist Jonathan Freedland argued that Diaspora Jews have a particular responsibility to critique Israeli actions, but to be effective, to be heard by Israelis, criticism has to be prefaced by expressions of love and care for Israel. Academic and one-time proponent of the academic boycott, Jacqueline Rose, took issue with this emphasis on love of Israel, and instead emphasised the greater need to express love universally. Sociologist David Hirsch, the founder of Engage, which campaigns against academic boycotts of Israel and leftist Judeophobia, emphasised the importance of "responsible" speech on Israel that avoids the anti-Semitism inherent in treating Israel as uniquely evil.

No one questioned the premise that the occupation was wrong, nor was there much discussion of the rights and wrongs of Zionism per se. As far as could be made out, the panelists and most of the audience appeared to agree on the pragmatic necessity of a two-state solution, even if many were not optimistic about its chances. Of course, those at the debate were not necessarily typical of the British Jewish community as a whole, but in the U.K. - as elsewhere in the Jewish world - there is a substantial constituency that is concerned about Israel's current course and seeks to find a way to influence Israeli policy and effect change.

The debate also illustrated how questions of strategy, tactics and above all language are the source of much of the divisiveness that characterises debate on Israel.

While there are huge differences of opinion between the pro-settlement Israeli right on one hand and one-state Islamists on the other, bitter disputes also divide even those whose long-term visions for Israel-Palestine are relatively similar.

This divisiveness can only get worse. The Gaza War and above all the prominence of Lieberman in the Israeli cabinet have provoked many people who have never before criticised Israel in public to feel compelled to do so. The proactive stance of Obama towards the Netanyahu administration has seen a tough counter-response develop from right-wing Diaspora Zionist groups who will not be silenced if any of the settlements are abandoned or if Iran develops nuclear weapons.

I have been working on a project called New Jewish Thought, which aims to improve the quality of dialogue on Israel among British Jews. The project was inspired in part by the U.S.-based Jewish Dialogue Group, which has pioneered "constructive conversations" about Israel in the North American Jewish community.

Israel has become the major source of dissensus in the Jewish world, bringing with it real threats to Jewish peoplehood and community. Jews urgently need to find a way to talk to each other on hugely divisive issues without abuse, recrimination, bitterness and hate. And that means working on the language we use to talk about Israel.

Dialogue is hard, many people are simply not interested, and talking is no panacea. However, it is one of the few ways of addressing a problem that, if it is not checked, could devour the Jewish world in a way that no dispute in Jewish history has done.