On a restaurant barge in the Nile, a small group of American Jews and members of the Egyptian business and political elite sat down for dinner a week after US President Donald Trump’s dramatic announcement that the United States recognizes Jerusalem as the capital of Israel. It was a friendly but challenging discussion.From our dinner companions’ perspective, the president’s speech was a provocative assertion of American dominance, a violation of international law, a breach of longstanding commitments to assume the role of honest broker in a destabilizing conflict that has gone on too long.My AJC colleagues and I pushed back. We pointed out that the president’s carefully chosen words did nothing to alter the status quo of Jerusalem, did nothing to curtail access to – or authority over – Muslim and Christian holy sites, did nothing to prejudice the negotiations that they and we agreed must be the vehicle to resolve the Israeli-Palestinian conflict.We cited the president’s affirmation that the ultimate borders of Jerusalem would not be set through US policy but would be subject to negotiation, as well as the fact that it will be years before a new American embassy can actually be built – and that it is abundantly clear its address will be in undisputed western Jerusalem. We said it’s absurd that Israel’s closest ally – or, frankly, any friendly country – cannot officially recognize its capital city while, at the same time, promoting a peace process that will determine whether an adjoining state can be established – and perhaps place its capital there, as well.What became clear as the evening wore on was that while we were defending the logic of the president’s action and the living reality of Jerusalem’s status, our counterparts were expressing an emotional response – defending the “ideal” of a Jerusalem divorced from its Jewish heritage and from the Jewish state that surrounds it, a divine place incompatible with Israeli sovereignty. And in a contest between reality and emotion, facts don’t win arguments.My colleagues and I had similar discussions in other Middle East venues, from the Arabian Gulf to North Africa, in recent weeks – before and after the president’s announcement – and came away with a deeper appreciation of the trauma that successive Arab defeats from 1948 onward, including the loss of Jerusalem’s walled Old City by the Jordanians in 1967, compounded by decades of official fantasizing about recapturing all of the Holy Land from what had been mythologized as Jewish usurpers, have inflicted on regional thinking.Through government pronouncements and clerical decrees, further legitimized by the occasional UN resolution, much of the Arab and Muslim world has convinced itself that the insult of Jewish presence, no less Jewish control, would be a passing phenomenon – in Jerusalem and throughout the land. That the world’s greatest power was now officially dispelling that fantasy was an unacceptable shock to those still in its thrall. My colleagues and I – and possibly the president and his advisers – expected that the reality and functional limits of recognition, the fact that it need have no bearing on final status-outcomes, would offset the symbolic, emotive shock that greeted the December 6 announcement.We were wrong – or, at least, we haven’t been proved right yet. We are waiting for reality to triumph. Evidently, it will take more time. It will also take leadership, especially by the moderate forces in the Arab and Muslim world – as have emerged in the Gulf and elsewhere – wise and brave enough to introduce an alternative narrative to their people, pushing back against the fantasists, the fanatics and the rejectionists. It will be a narrative of acceptance and cooperation, a narrative in which Israel is no longer an imposition in their region or a reminder of its weakness, but a partner in security, stability and development.It will take leadership on the part of Israel, continuing to reach out to its neighbors not only in the Arab states but among the Palestinians as well, in the same spirit that animates the mostly unheralded Israeli medical rescue of thousands of Syrian victims of that country’s civil war, and that underlies the close intelligence and strategic coordination between Israel and Jordan, and Israel and Egypt, in the fight against regional terrorism and an increasingly aggressive Iran.And it will take resolute, patient, skillful and respected American diplomacy, with the sensitivity of experienced diplomatic personnel, to calm irrational fears, find and empower promulgators of the new Middle East narrative, build and nurture mutual respect and interdependence, and establish the framework and the trust to advance enduring peace.The anger and skepticism my colleagues and I encountered over dinner on the Nile is the product of generations. It will not easily be erased. But consistent leadership and follow-through – by all stakeholders – can remake this troubled, vital region. Nothing else will.The writer is the American Jewish Committee’s associate executive director for policy.