Like any good family, the Jewish people have shown time and again how we can unite in times of crisis. When Israel faced its enemies on the battlefield or when Jewish communities abroad have been threatened, we have come together and recognized our collective responsibility for one another.But if this alone is the nature of the ties that bind us, it constitutes a failure of vision and of leadership. To define ourselves only by the threats we face is to allow our adversaries to define us. It is a definition founded in fear. This may be a mechanism for Jewish survival but it is not a prescription for vibrant and meaningful Jewish living.The writer is leader of the opposition and head of the Kadima party.Israel – as the homeland of the Jewish people – has a central role to play in developing a positive and unifying vision for the Jewish world. And yet, in my meetings with Jewish leaders and citizens from around the world I have been struck by the growing sense that Israel’s place in Jewish life is eroding.For too many young Diaspora Jews that I meet, Israel is not the source of pride or inspiration that it was for their parents’ generation. Living in vibrant Jewish communities abroad – within states that embrace multiculturalism and respect religious and minority rights – too many Jews no longer feel they need Israel as a safe haven or as an anchor for their identity. What’s more, they feel they have been taken for granted – their loyalty to Israel is expected, but their voice and their concerns are not heard.Within this country, identity is increasingly pulled between two poles: one, a secular Israeli identity centered around army service and the Hebrew language; the other a growing but narrowly defined Orthodox or haredi Jewish existence. In the process, a common commitment to the ideas and values that unite us as a people and that can resonate with Jews here and around the world seems increasingly tenuous These trends should alarm anyone who cares about the unity and future of the Jewish people. They not only threaten to fragment the Jewish people, but they place the Jewish communities here and in the Diaspora on radically different trajectories which undermine and weaken both.THIS STATE of affairs requires a dramatic reframing of the role of Israel in Jewish life and the nature of the relationship between it and world Jewry that should be built around four key principles: First, if Israel is to realize its mission as the national home of the Jewish people, it must act like one. It must find ways to welcome rather than alienate Jews regardless of their opinions or the stream of Judaism with which they are affiliated. It must embrace an inclusive and pluralistic Jewish agenda that respects our traditions without denying the legitimacy of difference.While Israel must retain its sovereign authority to determine its own future, decisions taken in Jerusalem that affect the Jewish people as a whole require that we listen to, consult with and take account of the concerns and interests of Jews beyond our borders.Second, the relationship between Israel and world Jewry cannot be founded on shlilat hagola (negating the Diaspora), nor on the mistaken idea that Israel is no longer central to Jewish life. For the first time since the Babylonian age, the Jewish people live in vibrant communities both in their ancient homeland and abroad. The relationship between these communities should be seen as mutually reinforcing rather than hierarchical.As Zionists, we must continue to encourage aliya, but we also have a vital interest in the vibrancy and welfare of Diaspora communities.Similarly, Diaspora Jews have a critical stake in Israel’s success and prosperity.This is not only because Israel must always be a place of refuge in times of need. It is also because Israel – through its rebirth and its very existence – gives sovereign expression to our people’s collective right to self-determination and creates unimagined opportunity for Jewish renewal, creativity and engagement with the world.Third, if we are to encourage a common sense of purpose and belonging, there must be a place within Jewish discourse for responsible criticism of Israel’s policies, even from overseas, without it being considered an act of betrayal. To equate supporting Israel with supporting the policies of any given government at any given time risks distancing Jews by forcing upon them a false choice between their commitment to Israel and their personal worldview. Israel is a confident and strong democracy and it is able to withstand and contain this kind of criticism.AT THE same time, those who criticize from within the family – those who criticize out of love – have responsibilities as well. They must be conscious of the fact that their criticism may be exploited for more sinister ends by Israel’s enemies and they should shape the context and form of their criticism accordingly. They must also show sensitivity to the excruciating dilemmas and constraints under which Israel operates and not fall victim to the double standards that so often characterize its critics.Fourth, and most important, while in many ways Israel has realized the Zionist vision of establishing a Jewish state, we have yet to succeed in creating a Jewish society. By this, I do not mean a theocratic society founded on Torah. I mean a society that is inspired by Jewish values, tradition and experience – a society that is a source of meaning, identity, culture and spiritual growth for Jews around the world, and a source of leadership and moral example for the world as a whole.It is a society that answers the questions of what we stand for and what we contribute not because we are threatened by enemies that seek to delegitimize us, but because we owe it to ourselves and our children. This is not just a project for Israelis, it is a project for Jews worldwide – it is a responsibility that both communities share and neither can abandon.In 1897, at the First Zionist Congress in Basel, the overwhelming majority of the Jewish people were able to unite around a profound idea that transformed Jewish history – the miraculous rebirth of a state for the Jewish people in their ancient homeland.It is time for us to embark upon a new Jewish conversation with that same revolutionary spirit – a conversation that recognizes that Israel and world Jewry are together writing the next chapter of Jewish history. It is within our power and our responsibility to generate that conversation and articulate a new Zionist vision that transcends political differences and gives expression to the unity and vitality of the Jewish people, its values and its potential.