One can't help but feel sad for Noah Feldman. In spite of his considerable professional accomplishments - a law professorship at Harvard, three books, a slew of well-received essays and a fellowship at the Council on Foreign Relations, to name a few - the young Jew is clearly stewing. A bubble of his own imagining has burst in his face. What he imagined was that, in its embrace of both Judaism and elements of contemporary culture, the "Modern Orthodoxy" of his youth granted Jews license to abandon as much of Jewish religious observance as they deem appropriate. Expressing his anger - coolly, to be sure, but the hurt seeps thickly through the poised prose - in a recent New York Times Magazine piece, "Orthodox Paradox," Professor Feldman describes how the Boston Jewish school he attended as a child and teenager went so far as to crop a class reunion photograph to omit him and his non-Jewish Korean-American fiancÃ©e, whom he later married. But the Photoshopped portrait is only the professor's anecdotal hook. What he really resents is that his erstwhile school, along with some of his mentors and friends, spurn him for his decision to marry outside his faith. No one, he admits, is rude to him. None of his former teachers or friends, he writes, would refuse to shake his hand. But he knows that they deride him for the life-path he has chosen. And that offends and perplexes him. Does not "Modern Orthodoxy," after all, embrace the "reconcil[iation of] Jewish faith with scholarship and engagement in the public sphere"? Should it not, therefore, regard his intermarriage as an expression, if somewhat extreme, of his effort at such reconciliation? Were he and his classmates not taught to see themselves as "reasonable, modern people, not fanatics or cult members"? Leaving aside whether un-"Modern" Orthodox Jews are in fact disengaged from the public sphere (a visit to any of a number of financial firms, law offices and hi-tech retail businesses in New York or other places with large ultra-Orthodox populations might yield evidence to the contrary), much less whether they are fanatical or cultist, Feldman's umbrage is misplaced. There is a reason why, to Orthodox Jews (and many non-Orthodox no less), no matter how embracing they may be of the larger world, intermarriage represents a deep betrayal. It is more than a violation of Jewish religious law. It is an abandonment of the Jewish past and an undermining of the Jewish future. Because marriage, arguably the most important choice in a Jewish life, is not a partnership but rather a fusing - "and they shall be as one flesh," in Genesis' words. Since a spouse is part of oneself, the personal consequences of intermarriage are profound. As, in Feldman's case, are the communal ones; his children are not Jewish. JUDAISM views the Jewish People as a special and hallowed entity. Members of the nation are to care for all - "we are to support the poor of the nations along with the Jewish poor," as the Talmud directs. And the righteous among the other nations, the Talmud goes on to teach, will receive their eternal reward. But the Jewish faith is clear about the ultimate redemption of the world: It is dependent on the Jewish People's remaining a nation apart in fundamental ways. One way is in our basic beliefs - for instance, that God gave our ancestors His law, and never subsequently changed it. Another is in our commitment to the integrity of the Jewish people qua people. Our commitment, in other words, to marry other Jews. A celebrated Orthodox television personality and pundit reacted to Feldman's article in a Jerusalem Post opinion piece with words of welcome. While he considers intermarriage "a direct threat to the very continuity of the Jewish people," he nevertheless considers Feldman "a prince of the Jewish nation"; and suggests that intermarrieds be treated no differently from the in-married, that they be offered our "love and respect." His suggestion stems from his Jewish heart but his Jewish head should have been more carefully consulted. Yes, there is ample reason to feel sympathy for Jews who intermarry. Transgressions performed from desire, Jewish tradition teaches, do not reach the level of those intended to be transgressive. And on a personal level, there are reasons to not cut off connections to intermarried friends or relatives. (It is not unheard of for non-Jews married to Jews to actually guide their spouses back to Judaism and to themselves convert; precisely such a couple is the subject of Migrant Soul, a biography I was privileged to write.) At the same time, though, there is simply no way - not in the real world - to warmly welcome intermarrieds without welcoming intermarriage. No way to make Feldmans feel accepted for who they are without making potential Feldmans view intermarriage as innocuous. No way to "devalue" the gravity of intermarriage without dulling the truth that every Jew is an invaluable link in the Jewish chain of generations. If one begins with the premise that intermarriage is dangerous to the Jewish people and the Jewish mission, the intermarried cannot enjoy our acceptance. There may be quibbles about the means by which we express our rejection of their choice. But the absence of any communal expression of reproach is nothing less than an invitation to intermarriage. TO MY lights, it doesn't seem extreme in the least for a Jewish school to make clear to an intermarried alumnus that, despite his secular accomplishments, it feels no pride in him for his choice to intermarry. I wouldn't expect an American Cancer Society gathering to smile politely at a chain smoking attendee either. It is painful, no doubt, to be spurned by one's community. It is painful, too, for a community to feel compelled to express its censure. Sometimes, though, in personal and communal life no less than in weightlifting, only pain can offer - in the larger, longer picture - hope of gain. The writer is director of public affairs for Agudath Israel of America.