In his 1782 book Letters from an American Farmer, John de Crèvecœur asked the most famous and important question in American history: “What then is the American, this new man?” The authentic American leaves behind him “all his ancient prejudices and manners, receives new ones from the new mode of life he has embraced, the new government he obeys, and the new rank he holds.” The American “entertains new ideas, and forms new opinions.” Crèvecœur was enthusiastic about this new man whose “labors and posterity will one day cause great changes in the world.”

Mark Twain, Henry James, and other of our greatest writers have contrasted American innocence, newness, and freedom with European sophistication, corruption, and fatigue. Our most famous folk hero, the cowboy, continually strikes out for the west, rejecting everything to the east, including Europe. Our language values change over tradition. To be a go-getter is better than to be a stick-in-the-mud. While British politicians stand for office, American politicians run for office. Twentieth-century politicians emphasized their break with tradition by naming their programs the New Nationalism, the New Freedom, the New Deal, and the New Frontier.

It is not surprising that some American Jews should reject much of their past and develop new forms of Jewish identity. The issue of identity is more problematic for them than for other Americans, since there is no agreement among Jews as to what is authentically Jewish or even who can be considered a Jew.

Do Jews comprise a religion, a race, an ethnic group, a nationality, or a cultural community with its own values, languages, and customs? Should people with a Jewish father but not a Jewish mother be considered Jews, as the Reform movement has declared, or is being Jewish dependent on matrilineal descent, as Conservative and Orthodox Jews believe? And what does Jewishness involve, when, as many have noted, the label “Jewish” is given to people of Jewish descent who have become entirely secular or assimilated or even deny being Jewish?

America, the land of the self-made man, is also the land of the self-made Jew. While American Jews have not generally thought of themselves as a chosen people, as this would hardly be the way to make friends and influence people, they certainly have been a choosing people when it came to defining their ethnic and religious identity. A United States senator named Cohen could choose not to identify as a Jew, while a black Jew named Greenberg could become the police chief of Charleston, South Carolina.

In America, Judaism was transmuted into a religious persuasion that could be modified, as one wag put it, at the drop of a hat (or skullcap). Jews became adept at selecting those aspects of Judaism and Jewishness that harmonized with their identity as modern Americans. The most popular of these did not interfere with their acculturation, did not make them conspicuous, and were attuned to democratic values.

In keeping with that development, the key element in the ethnic and religious identity of some Jews during the 1950s and 1960s was their support for the civil rights movement. They pointed to the murdered civil rights workers Andrew Goodman and Michael Schwerner as models, even though Goodman denied that he was motivated by anything Jewish and Schwerner disowned even being Jewish, preferring to call himself simply a human being. For still other Jews, Jewish identity has revolved around such secular causes as lobbying for Israel, fundraising for Jewish communal institutions, fighting anti­-Semitism, and venerating the victims of the Holocaust.

It is the various choices Jews have made that most interest historians, sociologists, demographers, and other onlookers. The historian Jenna Weissman Joselit, for example, in her fascinating 1994 book The Wonders of America: Reinventing Jewish Culture, 1880–1950, emphasized the penchant of American Jews to invent and then reinvent Jewish identity. In America, Jewishness became “a malleable and protean social construct,” stemming “as much from American notions of consumerism, gender, privacy, and personal happiness as from Jewish notions of tradition, ritual, memory, and continuity.” This combining of “the immediate and the transcendent, the quirky and the hallowed” was “virtually without parallel in modern Jewish history.”

This process extended to Judaism. New forms of Judaism emerged in America, including Reconstructionism, Conservative Judaism, Modern Orthodoxy, and humanistic Judaism. Hanukkah, a previously minor holiday, became a major event on the American Jewish calendar in part because, coming in December, it coincided with Christmas and its orgy of gift giving. (Hanukkah had an advantage in this respect since it lasted not one day but eight.)

The defining of Jewish identity did not become important until the nineteenth century. Before then virtually everyone, Jews as well as Gentiles, agreed that what distinguished Jews was their religion. But the Enlightenment emphasis on reason, the rise of socialism, the growth of nationalism, the emergence of the modern secular state, and the impact of social and economic modernization challenged traditional religion and gave rise to a host of competing ideologies of Jewish identity, many of which were secular and even antireligious.

This will strike many Christian readers as strange. Isn’t the term “secular Judaism” a contradiction in terms? If a Christian is secularized and becomes an atheist or an agnostic, he ceases being a Christian. Shouldn’t the same be true of Jews? But a Jew who rejects Judaism, and many of the fiercest critics of Judaism have been Jews, remains a Jew in good standing in the eyes of fellow Jews. Elaine Marks, a professor of French at the University of Wisconsin, indicated just how far notions of Jewishness could be stretched. Central to her sense of Jewishness was her apostasy. “I am Jewish precisely because I am not a believer,” she said paradoxically, “because I associate . . . the courage not to believe with being Jewish.” The non-Jewish Jew, to use Isaac Deutscher’s terminology, becomes in Marks’ telling the most committed of Jews.

Throughout the twentieth century, peoplehood has generally trumped religion when it comes to defining Jewish identity, and Jews took pride in their religious dissenters. Albert Einstein, a religious skeptic, was arguably the Jew most widely admired by other Jews during his lifetime. He was offered the presidency of the Hebrew University in Jerusalem, and the medical college of Yeshiva University, the leading American Orthodox institution, bears his name.

There are limits, however, as to how far definitions of Jewish identity may be stretched. Converting to another religion will remove a Jew from the Jewish people, at least in the eyes of other Jews, while becoming an atheist, an agnostic, or professing an antireligious ideology such as Marxism will not. Jews in the messianic Jews for Jesus movement might argue that their Jewish background logically leads to their becoming Christians, but such claims are rejected by Jews who perhaps remember Heinrich Heine’s witticism that no Jew could become a good Christian because no Jew would believe another Jew could be God.

The contemporary tendency to conflate Jewishness with Judaism and Jews with religious believers is a particularly American phenomenon. This is true today even though the majority of American Jews reject both the beliefs and the practices of normative Judaism. In Israel, by contrast, everyone recognizes that there are two types of Jews, the religious and the secular. During the late nineteenth and early twentieth centuries, approximately two million Jews from Eastern Europe immigrated to America.

Legend has remembered these immigrants as pious souls, but this was hardly the case. Many Jews living in Eastern Europe by 1900, and perhaps most of them, were well along the path of modernization, acculturation, and secularization. They might have continued to identify as Orthodox Jews, but often did so more out of inertia than conviction, and also because Orthodoxy was an integral aspect of Eastern European Jewish culture, which they looked back to with a certain degree of nostalgia.

Religious laxity increased exponentially in Eastern Europe during the late nineteenth and early twentieth centuries, and the atrophying of Orthodoxy created in Jewish identity a vacuum that was partially filled by a host of competing secular ideologies. Expressive of this is the musical Fiddler on the Roof, in which of Tevye’s three married daughters, only one lived as a traditional Jew. One married a Gentile in a Russian Orthodox church and became estranged from her family, and the other married a revolutionary committed to the overthrow of the tsarist regime.

Remaining in East Europe was still, in the eyes of the rabbis of the time, preferable to settling in America, a trefa (impure) land where Jews work on the Sabbath and eat non-kosher food. Such warnings, as one might have anticipated, were ineffective. The conditions in Europe were too bleak and the opportunities in America too bright for such advice to be taken seriously, and, in any case, it was precisely those Jews most unshackled from religious orthodoxy and least likely to listen to rabbinic admonitions who were most likely to emigrate.

A significant minority of these Jewish immigrants, then, came to the United States imbued with various nonreligious and even antireligious ideologies, including socialism, communism, secular Zionism, and diaspora Jewish nationalism. None of these had much relevance to American social, economic, and political conditions and were, in their pristine versions, generally one- or two-generation phenomena.

The history of Zionism is particularly revealing. The modern secular Zionist movement emerged in Europe in the late nineteenth century in response to growing anti-Semitism and worsening economic conditions. Zionists argued that the only solution for the Jewish “problem” in Europe was to transplant Jews to Palestine, the ancestral Jewish homeland. The ideology of secular Zionism had little appeal to American Jews, who had no intention of leaving the United States for life in Palestine. If America was not the Promised Land, it was certainly a land of promise. Here anti-Semitism was far weaker than in Europe, and, in any case, it did not seriously impede their economic and social advancement.

Instead of themselves settling in Palestine, American Zionists raised funds to help other Jews settle in Palestine. American Zionism became not a movement of national revival but a philanthropy. For Israelis such as David Ben-Gurion, American Zionism was not truly Zionist, since it rejected the fundamental Zionist principles of negating the diaspora and urging the ingathering of the exiles into a Jewish state. The Israeli statesman Abba Eban quipped that, after the establishment of the state of Israel, American Zionism had demonstrated the truth of a fundamental religious belief: that there could be life after death.

The story was even bleaker for left-wing, Yiddish-speaking Jews who hoped to transplant their institutions and ideas to the friendly soil of America. The history of socialism in America, in contrast to its history elsewhere, is a story of failure. As the world’s largest industrial power, the United States should have been open to socialist panaceas. If socialism failed in America, Jewish socialism was doubly doomed, since it was embedded in an immigrant secular culture that would inevitably disappear.

But for a few decades during the early twentieth century, it was possible for an immigrant secular Jewish leftist to live in an encapsulated world of like-minded persons, a world believed to be part of the wave of the future. Each of the various leftist Jewish movements had its own schools, summer camps, publications, and even neighborhoods. Between the two world wars there were in the Bronx four separate apartment complexes inhabited by Jewish families professing different versions of socialism ranging from worker’s Zionism to communism. One of these families was headed by a house painter named Myerson, whose daughter Bess was named Miss America in September 1945.

These immigrants’ radical secular Jewish identity began dissolving almost immediately on their arrival in America. The best indicators of Jewish acculturation were to be found in the pages of the Forward, the most widely read American Yiddish newspaper and the most popular foreign-language newspaper in American history.

From February through April 1905, the Forward published some fifty letters to the editor on the momentous question of whether a freethinker should assist a religious coworker with his work on Friday afternoon so that the religious individual could arrive at home in time for the Sabbath. That a socialist and nominally antireligious paper would open up its pages to such a debate is surprising, and so were the sentiments of some of its readers. While some said that giving any assistance would encourage religious fanaticism and intellectual darkness, others said that in America freethinkers should be tolerant toward the misguided and try to wean them from their religious foolishness.

Another issue debated in the pages of the Forward was how a socialist organization should respond to members who attend religious services, since they were betraying their organization’s principles. Here again, tolerance toward the misguided was recommended. A more interesting question was why these individuals would attend such services in the first place. One answer was provided by a joke that recounted how Abraham, a member of the Arbeiter Ring (Workmen’s Circle, a socialist Jewish mutual-benefit organization), was berated by another member after he was seen leaving a synagogue. In defense, he pointed to his synagogue-going friend Jacob. “Jacob,” he said, “goes to synagogue to talk to God; I go to synagogue to talk to Jacob.”

But after World War II there were fewer and fewer Jews who, like Abraham, craved speaking Yiddish with fellow immigrants. The world of secular left-wing Jewish culture was destroyed by acculturation and social and economic mobility, and the Holocaust murdered those potential immigrants who might have temporarily rejuvenated it. American secular Judaism lived on only in a host of novels, memoirs, and histories, most notably Irving Howe’s World of Our Fathers, published in 1976.

The Yiddish newspapers, the summer camps, the schools, and the mutual-benefit societies are now gone or are hanging on by their fingertips. By the 1950s and 1960s, Abraham’s prosperous and English-speaking descendants were safely ensconced in suburbia, where attending religious services was a norm of middle-class behavior. More than anything else, they wanted to be considered good Americans, and to be a good American required that one at least go through the motions of being religious. Americans were, as the Pledge of Allegiance stated, “one nation under God.”

The immigrants’ faith in socialism was transmuted into their children’s faith in liberalism. This development had been portended by the Forward’s endorsement of Franklin D. Roosevelt in 1936. Socialist true believers were horrified that an ostensibly socialist newspaper would endorse the candidate of a capitalist political party. The endorsement was evidence of the Forward’s acculturation and of its recognition that socialism was neither relevant nor important to its increasingly Americanized readership.

With the collapse of left-wing secular Judaism in America, religious Judaism came to the fore as the most popular way for Jews to define their Jewish identity. This does not mean that American Jews had suddenly become more religiously observant, only that increasingly they saw religion as the key element of their Jewishness.

Will Herberg’s influential 1955 book, Protestant-Catholic-Jew: An Essay in American Religious Sociology, reflected this new mood. Herberg described Judaism as one of America’s three great religions. Conflating Jewishness with Judaism, he ignored the manifold nonreligious ways by which Jews had defined and lived out their Jewish identity. He wrote at a time when Judaism seemed to be flourishing, and when each of the major Jewish denominations—Reform, Conservative, and Orthodox—exhibited or would soon exhibit a sense of triumphalism. In academia, this equating of Jewishness with Judaism could be seen in the common practice whereby departments of religion offered courses in Jewish studies even when the courses focused on sociology or history.

Reflective of Judaism’s now elevated status among Jews was Stephen J. Whitfield’s perceptive In Search of American Jewish Culture, published in 1999. Only religion, he asserted, provided the core of a viable and meaningful Jewish culture. “There is simply no longer a serious way of being Jewish—and of living within Jewish culture—without Judaism,” he claimed. “As the various secular bases of Jewish life have vanished or have been discredited, religion alone remains standing.” Any attempt to resurrect an ideology of secularist Jewish identity “looks like the future of an illusion.” He concluded that “what makes Jews different is, finally and fundamentally, only Judaism. . . . A Jew is someone who subscribes to Judaism. Period.”

Judaism is “irrepressible,” Whitfield wrote. Recent demographic studies indicate that it is not. The latest of these, A Portrait of Jewish Americans, published by the Pew Research Center last October, emphasizes that a growing percentage of American Jews are alienated from Judaism. Of the nearly thirty-five hundred surveyed, over one-fifth claimed to have “no religion,” and these religious dropouts were disproportionately found among younger respondents. While 93 percent of those born before 1927 identified themselves as Jewish because of religion, only 68 percent of those born after 1980 did so. Increasingly, it would appear, American Jews believe Jewishness revolves around culture and ancestry rather than religion.

A majority said it was not necessary to believe in God to be Jewish. Only 19 percent believed that observing Jewish law was important, while 42 percent thought that having a good sense of humor was essential to their Jewish identity. Evidently Jerry Seinfeld, Joan Rivers, and Sarah Silverman have trumped the Almighty and Maimonides. Nevertheless, while the “nones” are estranged from Judaism, they remain strongly connected to the Jewish people and the State of Israel and claim to be proud to be Jews. They form a large potential constituency for various versions of contemporary secular Judaism. The title of the Pew survey is itself revealing: not “American Jews” but “Jewish Americans.” “American” is the noun, not the adjective.

The status of contemporary secular Judaism is the subject of a fifty-two-page article in the 2012 American Jewish Year Book titled “American Jewish Secularism: Jewish Life Beyond the Synagogue.” The authors—Barry A. Kosmin, director of the Institute for the Study of Secularism in Society and Culture at Trinity College in Hartford, Connecticut, and Ariela Keysar, the institute’s associate director—are clearly secular partisans, although the institute self-identifies as “nonpartisan.”

In their article, Kosmin and Keysar claim that contemporary secular Judaism, through the use of “pluralistic market forces and the new information technology,” is invigorating American Jewishness and creating “new ties and forms of community” distinct from those involving religion. No longer can secular Jewishness be considered a vestige of the immigrant experience or a step on the road to assimilation and acculturation. Rather, it is an organic and vibrant cultural phenomenon that provides a way for Jews to express their Jewish identity in a nonreligious manner.

These Jews are the audience for Jewish museums, Jewish community centers, Jewish concerts featuring Klezmer and Sephardic music, Jewish film and book festivals, Jewish book clubs, Jewish websites, all-day Jewish television programming, and Jewish-studies courses in colleges and universities. Contemporary Jewish secularism, Kosmin and Keysar note, comprises “disparate communities” and “takes multiple forms and varies across different contexts and social environments.” It is “malleable and flexible” and “rich and diverse.” This flexibility and openness is undoubtedly one of its greatest strengths. But it is also one of its greatest potential weaknesses, since a movement without clearly defined boundaries runs the risk of becoming vacuous. What, after all, is distinctively Jewish about watching Seinfeld or Curb Your Enthusiasm? Don’t Gentiles do the same?

In preparing their essay, Kosmin and Keysar received assistance from the Posen Foundation, as did David Biale in writing his Not in the Heavens: The Tradition of Jewish Secular Thought, published the year before. Posen’s financial support of scholarly efforts to uncover the sources of Jewish secularization “have had an enormously stimulating effect on a generation of Jewish Studies scholars,” Biale notes. The foundation underwrites seminars and courses on secular Jewish culture at Brandeis, Harvard, Brown, and a couple of dozen other American universities.

Felix Posen, the wealthy British Jewish philanthropist who endowed the foundation, denies that it is antireligious. It is, instead, he argues, pro–Jewish culture, which is heavily secular. “I feel completely comfortable studying Judaism,” Posen said. “I just don’t believe in it. It’s part of our culture. . . . I have to stress that I will have nothing to do with anyone who is anti-religious. I’m only interested in the positive aspects of our culture.”

Today’s secular Judaism is different from that of the immigrant generation of the late nineteenth and early twentieth centuries. It is less ideological, less political, and less hostile to religion. Secular American Jews have worked out a modus vivendi with religion and often incorporate religious ideas and customs, suitably secularized, into their programming. They acknowledge that religion is a major element in Jewish culture while rejecting the claim that the essence of Jewishness lies in religion.

Nor is contemporary Jewish secularism in America deeply ideological. Secularism, Biale notes, is a response to the peculiar American emphasis on “self-fashioning and self-invention” and not to philosophical constructs. America is, after all, the land of William James and John Dewey and the birthplace of philosophical pragmatism. “The hallmarks of secularism in America,” Biale writes, quoting Amos Oz, “are lack of dogma and resistance to uniformity. . . . No hegemonic authority, either religious or nationalist, can dictate its agenda. No trajectory toward the future can be charted with confidence. Secularism can make no promise of continuity or survival, but it does guarantee the freedom to experiment, without which neither continuity nor survival is possible.” According to Laurence J. Silberstein, a professor of Jewish studies at Lehigh University, contemporary Jewish secularism prizes “process over product, multiplicity over unity, and becoming rather than being.”

The key question regarding Jewish secularism in America is whether it has any future. Can its devotees pass on to their children and their children’s children an interest in the artifacts of secular Jewish culture? Israel’s secular Jews have a state to protect, a language to speak, a culture to preserve, and a strong sense of nationality. America’s secular Jews have none of these. Is it likely that a love of Jewish-themed movies, an interest in Yiddish literature or the history of the Holocaust, or fond memories of visiting Jewish museums can provide a lasting Jewish identity?

With Jewish identity increasingly a matter of ascription rather than prescription, what likelihood is there that, outside the traditionally religious, there will ever be enough Jews choosing the same things to constitute a community? What will be the cement of community when Jews come to believe that Jewishness sanctions whatever is the cultural rage of the day? Secular Judaism appears to be a Jewishness without boundaries. So far it has not been acceptable to be a Jewish Christian, but, in light of a skyrocketing intermarriage rate, is there any certainty that this will continue? Already there are Gentiles on the board of directors of some Reform congregations.

Judaism as religion might not be the entirety of Jewish identity, but it is difficult to imagine a vibrant Jewish identity completely severed from it. Certainly this is what the social-science literature would seem to indicate. The fastest growing segments of American Jews are the nones and the Orthodox, and the potential constituency for secular Judaism appears to be limited.

“Outside of Israel, where secularism flourishes in the hothouse of nation-building,” writes the journalist Andrew Silow-Carroll, “the Jewish future belongs to religion.” If this is so, then future estimates of the American Jewish population will have to be revised dramatically downward. As the Talmud warns, with the passing of the prophetic age, prophecy became the province of the childish and the foolish, but one can safely make one prediction: The issue of Jewish identity will continue to be salient.

Edward S. Shapiro is professor of history emeritus at Seton Hall University.