Orthodox Judaism was supposed to fail in America: Jews appeared destined to lose their identity in the melting pot along with other immigrants. America’s genius for assimilation persuaded Eastern European rabbis to denounce immigration; Jonathan Sarna of Brandeis University has translated a tract entitled “People Walk on Their Heads,” by a rabbi who visited America and was aghast at what he observed. Nor were these fears idle: Sarna cites a 1952 study claiming that only 23 percent of all Orthodox children planned to remain Orthodox; nearly half planned to join the Conservative denomination.

Yet Orthodox Jews today comprise a third of all self-identified Jews ages 18 to 34 and well may constitute a majority of all American Jews in another two generations. The Orthodox ascendancy in the face of almost all expectations is one of the strangest and most singular events in religious sociology and also one of the most inspiring: Many of the brightest and most passionate young American Jews have embraced the ancient observances of Judaism. Most remarkable of all, perhaps, is that most members of the new generation of Orthodox Jews have found it possible to engage the secular world at the same time that they live true to the Torah of Israel. As the Orthodox chaplain at Harvard Hillel, I have seen a fair sampling of the young Jewish leaders who comprise the future of Orthodoxy and, by implication, of American Judaism.

Not until the appearance of the National Jewish Population Survey (NJPS) of 2000“2001 did the underlying strength of Orthodoxy register with the Jewish world at large. The year 2000 was also the year in which an Orthodox Jew ran for the vice presidency of the United States. The NJPS placed the percentage of American Jews who define themselves as Orthodox at 10 percent of the total Jewish population. In addition, another 21 percent of Jewish households belong to an Orthodox synagogue. What is perhaps most stunning is that 34 percent of Jews within the age bracket of 18“34 identify with Orthodoxy.

What changed in the half century since 1952? If anything, the America of today is even more pluralistic than the America of the 1950s. The majority of Americans of Jewish descent have embraced cultural diversity and tolerance with more passion than has the population at large. The Orthodox have never been at greater variance with the Jewish majority. The sociologist Steven M. Cohen of Hebrew Union College notes that, for most American Jews, religion offers “no final answer” and “no irrevocable commitments.” They “decide week by week, year by year, which rituals they will observe and how they will observe them.” Their “principal authority,” Cohen continues, is the “sovereign self,” and even those who observe some part of their religion express “discomfort with the idea of commandment, all the more so with the notion of particular commandments issued by God to Jews alone,” what Jewish tradition defines as the “Torah covenant at Sinai.”

In contrast, writes Samuel Heilman of the City University of New York, Orthodox Jews

are highly affiliated to all things Jewish. For them, Judaism is not primarily a personal matter. On the contrary, it is a series of mandates: requirements whose origins are considered to be part of a venerated tradition that sets definite criteria for how each person must act and live, regardless of personal wishes and inclinations. This is a life with people who are rooted in obligations to what some of them have come to call “Torah-true Judaism,” a Judaism linked inextricably to a way of life determined by the Halacha [Jewish law].

Orthodox Judaism was supposed to founder on rugged American individualism, but quite the opposite has happened: A Judaism assembled at a buffet of individual preferences has small interest for young adults seeking direction and meaning in their lives. Young Jews are likely either to abandon their religion altogether or to take it seriously. That is why there is a migration to Orthodoxy by young Jews raised in liberal or secular households.

There is nothing else in the modern religious experience to which to compare the Orthodox Jewish revival. From a sociological standpoint, it seems improbable that a religious practice requiring a separate, private educational system conducted to a large extent in a second language would generate so much worldly success. Torah-observant Jewish practice in some respects constitutes a countercultural extreme, centered as it is on a different rhythm of life and a different sort of community (restrictions against travel on the Sabbath require Jewish homes to cluster around a nearby synagogue). Torah study, which locates every generation of Jews in the revelation at Mount Sinai, takes up a great proportion of students’ time and mental energy. Just as striking as the strength of religious observance in Modern Orthodoxy is a growing degree of worldly success. Modern Orthodox day schools send a disproportionately large share of graduates to the Ivy League; the Manhattan flagship day school of Modern Orthodoxy, Ramaz, has the highest acceptance rate to top colleges of any high school in the United States. Because the Modern Orthodox are profoundly secure in their religious observance, they can engage the modern world with self-confidence. The exhaustive educational prerequisites for Orthodox practice build habits of mind that foster future accomplishments in the professions and business.

I have had the privilege to walk a bit of the journey alongside Jewish college students grasping for a relationship with God who find that traditional Judaism makes possible such a relationship. According to the Jewish campus organization Hillel International, about a quarter of undergraduates at Harvard University are Jewish. Some of them never venture into Harvard Hillel; most of the ones that do had no experience of traditional Judaism at home and encounter it at college for the first time. Time and again, I observe that dissatisfaction with the “profound individualism” and religious ambivalence that has shaped liberal Judaism brings them into conversation with Orthodox Judaism.

The demographic bulge of 18“ to 34“year-olds among Orthodox Jews has the undivided attention of religious leaders. The past president of Hillel International, for example, is now the president of Yeshiva University, an academic center of Modern Orthodoxy. In fact, the future character of Orthodox Judaism”and perhaps American Judaism in general”is now in gestation on college campuses. Modern Orthodoxy is not the only force in Torah-observant campus life. Chabad, the Hassidic organization devoted to Jewish outreach, claims to host more than 5000 students a week at its Sabbath meals.

With the increased numbers, visibility, and confidence of Orthodox Judaism comes a profound challenge: The Orthodox world must decide how to engage decisive issues from within the commitment to tradition and continuity of Jewish law that defines Orthodoxy. A source of anguish to many in the Orthodox community is the role of women in religious life. Whether Halacha permits the ordination of female rabbis remains the subject of heated contention. Other issues on which the Orthodox world is divided include interfaith dialogue, academic study of classic Jewish texts, and the debate between dedicated full-time Torah study or pursuit of a secular profession. Many of these fall into the meta-question: How and in what way can Jews lead a life true to Torah while engaging the larger society and culture?

There is good cause for optimism that Modern Orthodoxy will resolve these issues, for we have had two centuries’ worth of preparation for what might be termed the Modern Orthodox movement in American Judaism. The meta-question of tradition versus modernity erupted into Jewish life at the turn of the nineteenth century, at the moment of Jewish emancipation from the European ghetto in the wake of the Napoleonic wars. Under the aphorism Torah im Derekh Eretz, or “Torah within the way of the land,” the program of Modern Orthodoxy was promulgated by the great nineteenth-century German rabbi Samson Raphael Hirsch (1808“1888).

Emancipation delineated a stark choice: to attempt to re-create the ghetto in a Jewish life utterly separate from the modern world, to “reform” Judaism into a universalist ethics, or to continue a Torah-observant life while engaging the modern world. Hirsch gave breath and vision to what would become known as German Neo-Orthodox Judaism. In his Nineteen Letters, he warned against living in the past of the ghetto, in “an uncomprehended Judaism, as practiced by men from habit, a revered but lifeless mummy which it is afraid to bring back to life.”

Hirsch’s program was not “either/or” but rather “both/and””modernity in the embrace of science, technology, and the institutions of the liberal modern state without compromise on Torah observance. Observance, it must be emphasized, means far more to the Orthodox than performance of the commandments, or mitzvot. Adherence to the Torah of Israel requires us to place ourselves within the unbroken dialogue between God and the people Israel, manifest in the oral Torah”the legal judgments and commentary of the sages of late antiquity through the Middle Ages and early modern period”that God gave to Moses on Mount Sinai along with the written Torah.

In nineteenth-century Germany, Jewish reformers substituted academic methods of text criticism for the revelatory experience of Jewish tradition, in the form of Wissenschaft des Judentums (“the science of Judaism”), the critical study of Jewish texts and culture. Despite their many contributions, the “scientists” of Judaism never could explain why a God subject to scientific analysis could command the passion and loyalty of the personal God of Jewish tradition. Reform Judaism, the outcome of this exercise, sought to reduce Judaism (as the 1885 Pittsburgh Platform of Reform Judaism stated) to a general sort of ethics. “We recognize in the Mosaic legislation a system of training the Jewish people for its mission during its national life in Palestine, and today we accept as binding only its moral laws, and maintain only such ceremonies as elevate and sanctify our lives, but reject all such as are not adapted to the views and habits of modern civilization,” the platform declared.

If Jews aim for nothing more than the “views and habits of modern civilization,” though, there is nothing but nostalgia to keep them within the Jewish community. Nostalgia evidently has an expiration date, for half of Reform Jews intermarry, and only a small minority of children of mixed marriages continues to practice Judaism.

The battle of integration and adaptation versus insularity and preservation was not fought only between the traditionalists (who would come to be called “the Orthodox”) and the new Reformers; it also was an impassioned debate within Orthodoxy itself. One solution is to isolate Jews from the world at large. In its extreme expression we encounter this approach in American Haredi communities, which produce their own teen fiction, soap operas, and popular songs in Yiddish in order to exclude all elements of the ambient culture. By contrast, the Orthodoxy of Samson Raphael Hirsch, according to the late Rabbi Dr. Isidor Grunfeld, was

a religious humanism. He denied the alleged contrast between Judaism and humanism. Neither the Written nor the Oral Law forbids us to enjoy this world or the beauty of its nature or take part in what amounts to real progress of the human mind. Hirsch was thus “lebensbejahend und wissenbejahend” [life-affirming and knowledge-affirming] . . . . There is, therefore, no contradiction between Judaism and humanism, that is, between the two sources from which our duties flow. Judaism is humanism on a higher place, ennobled by the Torah. Judaism and humanism need one another and supplement one another . . . . From this follows a positive attitude by Judaism to life, joy and happiness, to the development of science, ethics and art among men.

The antipode to Hirschian neo-Orthodoxy within the nineteenth-century Jewish world was Rabbi Moses Sofer (1762“1839), known around the world as the “Hatam Sofer,” who was the rabbi of the city of Pressburg (present-day Bratislava, capital of the Slovak Republic). Rabbi Sofer excluded from the rabbinate anyone who read secular books or who delivered sermons in a “foreign language.” Rabbi Akiva Yosef Schlesinger (1837“1922), one of Rabbi Sofer’s intellectual heirs, went even further: He claimed that the “language of the nations [that is, non-Jews] as well as the science of the nations are included in the prohibition against going in the ways of the gentiles, and their adoption by Jews was also a profanation of the name of God.”

One outstanding intellectual leader laid the foundations for the strength of Modern Orthodoxy in the United States: Rabbi Joseph Soloveitchik (1903“1993), the “Rav” of Yeshiva University’s Rabbi Isaac Elchanan Theological Seminary, who trained thousands of rabbis during a half-century career. The heir to the Brisk dynasty of Lithuanian rabbis, Soloveitchik earned a Ph.D. in philosophy at the University of Berlin and was equally at home in the world of Western philosophy and the traditional world of Talmud. His philosophy, which became known as Torah u’Maddah (Torah and science), bridged modern science and a profoundly traditional commitment to Torah. Rabbi Dr. Samuel Belkin, the second president of Yeshiva University and a close friend of Rabbi Soloveitchik’s, wrote the following about the inextricably linked nature of Torah and science:

We therefore believe that the moral laws of the Torah, the concepts of universal justice of the prophets, and the spiritual and religious philosophy of saints and sages throughout the ages can serve as the medium for the unification of knowledge and as the blueprint for an ideal society. Such knowledge is godly, and divine knowledge alone can lift our personalities, elevate our secular learning to a higher spiritual stratum. The more we learn to study of the material world, the more we concentrate on applied sciences and technology, the greater is our responsibility to promote, by religious education, the power and importance of the moral and ethical values which lead us irresistibly to an ideal evaluation of men and things.

No bright line divides Modern Orthodoxy from the isolationist Haredi form of Judaism. The two communities still remain in relationship with each other, pray at each other’s synagogues, attend each other’s life-cycle events, and often form part of the same families. An increasing number of Haredim are leaving the cocoon of the yeshiva world to learn secular skills, and a large number of Modern Orthodox youth are conducting part of their education at Haredi yeshivas in Israel. The gravitational pull between the two camps runs in both directions. The Haredim are playing an increasing role in Jewish education: The teachers at many Modern Orthodox day schools include an increasing number of Haredim. This is due, in part, to the emphasis on economic success in Modern Orthodox families, which discourages many young Orthodox Jews from entering what is perceived to be the low-paying field of education. Many young adults, after returning from a post“high school year abroad studying Torah in Israel, display the Haredi passion for total devotion to religious study.

A flurry of articles predicting the death of Modern Orthodoxy appeared a decade or so ago”a premise devastatingly refuted by subsequent events. Torah im Derekh Eretz has more traction in twenty-first-century America than at any other time and place, for the simple reason that young American Jews are seeking a path that remains firmly planted in Torah observance while fostering their engagement with the positive accomplishments of modernity.

In 1997, Rabbi Avraham Weiss of the Hebrew Institute of Riverdale”an 850-family Modern Orthodox synagogue in New York”published a groundbreaking essay in the journal Judaism entitled “Open Orthodoxy! A Modern Orthodox Rabbi’s Creed.” In his essay, he laid forth a vision for reinvigorating Modern Orthodox Judaism and reasserting it not as a compromise between Haredi Judaism and assimilation but as an ideal form of Orthodox Jewish practice. He stated:

In each of these ideological realms, the common denominator that distinguishes Modern Orthodoxy from the Orthodox Right is openness. Modern Orthodoxy is open to secular studies and views other than those of their rabbis; open to non-Jews and less observant Jews; open to the State of Israel as having religious meaning; open to increased women’s participation; open to contact with the Conservative, Reform, and Reconstructionist movements; and open to public protest as a means of helping our people . . . .

For the Open Orthodox Jew, true and profound religio-legal creativity and spiritual striving emerges from the tension between the poles of strict halakhic adherence and open ideological pursuits. They appear to be opposites when in fact they are one.

Two years later, Weiss founded Yeshivat Chovevei Torah (YCT) Rabbinical School, the first Open Orthodox rabbinical school. In the past ten years, YCT has ordained fifty-four rabbis who now serve as synagogue rabbis, heads of communities, campus rabbis, and teachers in schools in the United States, Canada, Romania, Hungary, and Israel. In addition, 2009 marked the founding by Rabbi Weiss of Yeshivat Mahara’t, the first seminary to ordain Orthodox female clergy. With Rabbi Marc Angel, the emeritus rabbi of New York’s Spanish’Portuguese Synagogue, Rabbi Weiss founded an association for Orthodox clergy: the International Rabbinic Fellowship (IRF), with about two hundred member rabbis.

These new institutions reflect the assertiveness of Modern Orthodoxy. Most important, though, is the experience of young Orthodox Jews, which I have had the privilege to share through my work at Harvard Hillel.

A growing number of young Orthodox Jews spend a year in intensive Torah studies in Israel. Many return with Haredi insignia: for example, changing their kippah from a knit one (typical of Modern Orthodox Jews) to one of black velvet (typical of Haredi Jews) and adopting a dress code of only white shirts and black dress pants. Their first response to the demands of a secular university is often ambivalent: They prefer Torah studies to secular classwork. My observation, though, is that their religious passion soon adapts itself to engagement with secular academics, while their yearning for Torah remains. Yeshiva study in Israel deepens their Judaism without detaching them from the secular world. Despite Haredi ambivalence to the State of Israel, Modern Orthodox youth who study in Haredi yeshivas in Israel return with an even more profound Zionist commitment.

Modern Orthodox students, moreover, are more engaged than ever in secular issues. My wife and I run a weekly program called Mishmar, in which we provide hot, home-cooked food paired with interactive learning opportunities for undergraduates. Two of our regular students, both products of Modern Orthodox homes in the tristate area and both serious about attendance at prayer services and Torah study sessions, told me before the beginning of the program that on one particular week they would be coming late because they did not want to miss an opportunity to hear Newt Gingrich, who was speaking on campus that evening. Young Modern Orthodox students understand that they must engage secular politics in order to make the world more hospitable to their concerns.

Respect toward non-Jews is a subtle but important dividing line between Modern and Haredi Orthodoxy, and here the Modern Orthodox standpoint is ascendant. During a class I delivered on Gentiles and Torah observance, at dinner in the kosher dining hall, a student asked me to lower my voice lest I unintentionally offend one of the non-Jewish students in the room. Sadly, Haredi rabbis too often live in a past in which mutual antagonism between Jews and Gentiles was unavoidable. The Modern Orthodox world is committed to respectful interfaith relations.

In the great debate within Orthodoxy over the role of women in religious practice, the Modern Orthodox effort to assign teaching and ritual leadership roles to women has strong support among young Orthodox Jews. My wife and I serve together as Orthodox advisers for the Orthodox community at Harvard Hillel. She takes an active role in the leadership of the community, from policy decisions to pulpit sermons. There have been no expressions of discomfort. On the contrary, my wife is perceived as being as much of a religious guide and role model to the students, both male and female, as I am.

No one can predict the Jewish future. The present strength of Torah im Derekh Eretz in America would have astounded its strongest proponents in the past generation. From my observation, though, the Torah-true path through the modern world, the path delineated by Samson Raphael Hirsch and Joseph Soloveitchik, has rallied such a large number of young Jews that we truly can speak of this time as being defined as the era of Modern Orthodoxy.

RABBI BEN GREENBERG is the Orthodox Jewish Chaplain of Harvard University and the Orthodox Rabbi of Harvard Hillel.