In the wake of the recent war with Hizbullah, Israel is going through a difficult but necessary process of self-examination. The questions are many, as are the lessons to be learned. But if American Jews do nothing more than follow the process in Israel with interest, they are losing an essential opportunity to learn a lesson of their own. The role of the United States was critical during this past month, as it has been for most of Israel's life. It's a lesson we need to take to heart. Nowhere in the United States Constitution is it written that the special US-Israel relationship is part and parcel of America's foundational principles. That's why I have never, not for a single moment, taken for granted America's unique ties with Israel, and why I have spent a good part of my professional life urging fellow American Jews never to succumb to complacency or the mistaken notion that the link is on automatic pilot. Nations have been known to reassess their geopolitical interests and do turnarounds. The best such example is France, which played a critical role in Israel's life in the 1950s and early 1960s and then concluded that its long-term objectives were best served by distancing itself from Israel and cozying up to the Arab world. That decision cost Israel dearly, but Israel was lucky. The United States stepped into the breach and has, particularly over the past four decades, played a unique, indeed indispensable, role in the life of Israel. BUT IMAGINE that the US had instead chosen to pursue an "evenhanded" approach to the region or, worse, followed France's example, arguing that the realpolitik of sheer Arab numbers, energy resources and export markets dictated such a turn. What would have been the impact on Israel? To be sure, Israel enjoys friendly relations with a number of countries, and, it should be added, a special link with Germany. But, truth be told, no nation could - or can - substitute for the US role. No other nation has been prepared to define such an intimate relationship with Israel in all bilateral spheres - from arms sales, foreign aid, and intelligence-sharing to a free-trade zone, scientific cooperation and diplomatic support. No other nation has the capacity, by dint of its size and stature, to help ensure Israel's quest for a secure and lasting peace and normalization in the community of nations. Has there been another permanent member of the UN Security Council prepared to exercise its right of veto, even if it stands alone, to ensure that Israel is not singled out unfairly by the one UN body that has legally enforceable powers? Was there another nation prepared to stand with Israel - and then walk out with Israel - when the UN Conference Against Racism, held in Durban on the eve of 9/11, turned into an anti-Semitic and anti-Zionist hatefest? Was there another nation ready to resupply the Israeli military during the Yom Kippur War, at a moment when Israel's fate hung in the balance? IN THE recent conflict with Hizbullah, once again the United States demonstrated its willingness to stand by Israel, provide vital support, and withstand the pressure of many US allies who would have wished for an earlier end to the fighting, even if it meant keeping Hizbullah largely intact and in place. There has long been a debate about the reasons for America's unique relationship with Israel and the strong support Israel enjoys in American public opinion. Some suggest that the primary explanation lies in the role of the American Jewish community; others believe that Israel's impressive record as a democratic nation and dependable US ally spells the difference; still others contend that it is primarily America's religiosity and link to the birthplace of the Judeo-Christian heritage; and still others insist that it largely derives from the personal chemistry between, say, a Lyndon Johnson and a Levi Eshkol or a George W. Bush and an Ariel Sharon. Whatever the primary factor, there can be no doubt that American Jewry is an essential element of the equation. This is all the more reason why American Jews need to work day in and day out to ensure that the mutually beneficial link goes from strength to strength. COULD THE bilateral relationship suffer the French fate? Not anytime soon, but it is obvious that there are those Arab and Muslim groups in the US who believe in the possibility of long-term change in America's Middle East orientation. That's why they are working so energetically in universities, for example, hoping to shape the outlook of future generations of American leaders. And in this, they're helped by the largesse of Saudi benefactors only too happy to establish footholds on elite campuses. And that's why they are trying to build links with labor unions, minority communities, the anti-war movement, former State Department Arabists and academics, believing that one day these efforts will create a new critical mass able to shift US foreign policy away from its special ties with Israel - and thereby undercut America's commitment to the only true democracy in the region. Friends of Israel in the US, including Jewish organizations, must remain alert to these efforts and mindful of their potential consequences. Let's face facts. Any major wedge driven between the US and Israel could have fateful consequences for Israel. Israelis, who surely have enough to think about at the moment, should nonetheless bear in mind the importance of the American Jewish community as a key player on this "second front." A.B. Yehoshua, speaking at the American Jewish Committee 100th anniversary celebration earlier this year, famously dismissed the relevance of American Jews to Israel's life and the Jewish people's future. He could not have been more wrong. The writer is executive director of the American Jewish Committee. Saul Singer is away this week.