An experienced Israeli general told an audience of several hundred young Jewish activists from around the world that Israel, despite the odds, has won wars and defeated terrorists. But when it comes to the current threat against the Jewish state, identified by the virtually unpronounceable word delegitimization, the combined capacities of Israel and the Diaspora are stuck.There is no question that Israel’s legitimacy is under increasing assault globally. With Palestinian leaders pressing for an internationally sanctioned unilateral declaration of independence at the UN in September, followed by the Durban III conference that is certain to single out Israel for unwarranted condemnation, it seems that the political tsunami Defense Minister Ehud Barak warned of is approaching fast.Unlike military battles, Israelis cannot confront the delegitizimation campaigns alone. If there ever were a need for a strong partnership between Israel and the Diaspora – Jewish communities worldwide – this is the issue. It is also a motivation to engage communities across generations.AJC Access, the young leadership division of the American Jewish Committee, and the Reut Institute of Israel, which has done pioneering strategic thinking on confronting the assault on Israel’s legitimacy, co-hosted the gathering in Washington, DC over the weekend. The 450 young Jews, in their 20s and 30s, from the US, Europe, Australia, South Africa, Latin America and Israel engaged in intensive dialogues with each other, with prominent experts and with Israeli officials.Some of the activists were reconnecting, but many were meeting for the first time. They departed enthused and eager to use the resources at their disposal, or develop new ones, to deepen understanding of Israel and strengthen the interconnectedness of Jews worldwide.Indeed, while the media have harped on the apparent successes of Arab youth using social media to encourage uprisings in their countries, why shouldn’t Jews use such 21st-century communications tools to make the case for the Israeli people’s quest to live in peace and security? Mobilizing the wider cohort of younger Jews, or, for that matter, even some who are a bit older, will require assertive outreach both to those already involved as well as to the vast numbers who are not yet engaged with what’s happening regarding Israel.Galvanizing effectively will also require stepped-up efforts at education – providing Jewish communities with the vital information that can make them better advocates for Israel. One eminent American professor who has taught about the Middle East for decades proclaimed that it is essential for Jewish youth to be as intimately familiar with Israeli history and current affairs as they are with the Seder’s four questions.In addition to the challenges facing younger Jews to both defend and promote Israel, as a French cabinet minister pointed out, is the burden that comes with the passing of the last living Holocaust witnesses, and imparting the knowledge of what happened. Francois Zimeray, France’s minister of human rights, stressed at the conclusion of the conference that denial of Israel’s legitimacy and denial of the Shoah are intertwined.Follow-up to such a global gathering is a challenge, but not insurmountable. With technology offering so many opportunities to stay connected, there is real hope that a worldwide network of advocates for Israel can be created to deal with the immediate issue of legitimacy, and then be sustained to address other pressing matters in a coherent manner. Ideally, what took place in Washington – this rare gathering of young Jewish adults from all corners of the globe – should be repeated. Of course, that takes a lot of resources, financial and human.If there are any doubts that this is realistic, recall the challenges confronting the pioneers, the halutzim, in the years immediately after the Shoah, and the early years of the State of Israel, given birth by the United Nations more than 63 years ago.That UN endorsement is one of the foundations of Israel’s legitimacy – a critical historical fact that a multigenerational worldwide campaign countering Israel’s detractors must reinforce. In this effort, disparate Jewish communities will have opportunities to take action as part of a collective will, confirming that the Diaspora is imperative to Israel’s success and, working together, to strengthening the Jewish people.The writer is the American Jewish Committee’s director of media relations.