In every generation, people shape their sense of themselves and their place in society within the frameworks defined by their local community and the larger national community. What does it mean to be white? What constitutes Jewishness? (Is it a race? An ethnicity? A religion? A nationality?) The answers to these questions are not fixed but rather are constantly shifting, especially in a modern context in which people have multiple, sometimes competing, identities.

Race may, at first glance, seem to be the most immutable identity – existing "in the blood" or written on one's skin – but it is actually fluid. Before the mid-19^th century, European immigrants to the United States were mostly absorbed into the white population, and Jews – though considered religiously "other" and often socially separate – were not viewed in racial terms. But the rise of mass immigration from Europe, beginning in the 1840s, brought in a new wave of immigrants too large to be easily assimilated, and this new social reality of large urban populations with a heavy European immigrant flavor led to a recasting of racial categories and relations. The ruling elite classes (predominantly wealthy, American-born Protestants) expressed their fears of "race suicide" as the "native" stock was infiltrated and overrun by these "inferior races" first from Ireland and then from Eastern and Southern Europe. This immigration wave brought nearly 2 million Jews to the United States, outnumbering the German Jewish elite who had arrived in the mid-19th century and transforming the American Jewish community, which had been predominantly Sephardic (of Spanish/Portuguese origin), into a predominantly Ashkenazi population, as it remains today.

The new racism that arose in response to the immigration wave was rooted in supposed science – intelligence tests and a eugenics movement that focused on breeding "better" people, as opposed to the "feebleminded" Eastern Europeans, Mexicans, Asians, Native Americans, and African Americans. This "scientific racism" justified the passage of legislation that outlawed Chinese immigration (Chinese Exclusion Act of 1882) and heavily restricted immigration except from Northern Europe (Johnson Act of 1924). The government and businesses limited the social mobility of those "inferior races" who had already settled in the US through policies such as quotas in higher education, corporate hiring restrictions, and, in the postwar period, federal housing loan policies that enforced racial segregation and subsidized the suburbanization of white populations.

In this context of changing perceptions of race, the racial identification of Jews underwent significant shifts. On one level, most Jews were always considered white in that they were permitted to become naturalized citizens – a right reserved only for "free white persons," according to the 1790 law set in place by the first Congress. But during the years of the large wave of immigration from Eastern and Southern Europe (roughly 1880-1924), Jews were counted among the many European groups (the 1911 Dillingham Commission Report on Immigration identified 36 different European races) classified as not quite white, or racially "other." (Some Jews, for example, were classified as "Hebrew.") Who fell into this racially suspect category depended on who was seen as different, unassimilable, or a threat to the nation, as well as who was perceived as providing essential (though devalued) labor. In the 1860s, the Irish were singled out for their savagery and racial weakness; by the end of the 19^th century, Jews often bore the brunt of anti-immigration racism, targeted as the racial scourge overrunning and infecting urban areas. Political cartoons, for example, often depicted Jews as dirty, diseased, and criminal. Though expressed in racial terms, this anti-immigrant sentiment also intersected with fears of the rising working class and of political radicalism.

This racial definition of Jewishness, though derogatory when applied by non-Jews, could also serve a positive purpose for Jews. Many Jews embraced race as something that united them – a kind of identity deeper than belief or religious practice, something primal, defying assimilation. Racial identification resonated with a Jewish sense of peoplehood – an identification that was not entirely captured by the definition of Jewishness as solely a religious identity – and fulfilled the desire to preserve a minority identity.

Soon after the Johnson Act effectively closed the door on immigration from anywhere but Northern Europe, conventional wisdom on racial classification moved toward the recognition of three main races: Caucasian, Mongoloid, and Negroid. This meant that the many different European races – including Jews – were consolidated into a monolithic category of Caucasian whiteness, and the primary racial distinction in America became the black/white binary.

Several factors led to this consolidation of whiteness. In light of the severe immigration restriction, those formerly considered "racially other" now posed less of a threat. Without a steady stream of new immigrants, the Eastern and Southern European populations were now predominantly American born, not immigrants themselves, and thus seemed less different and more easily assimilable. At the same time, the Great Migration of African Americans from the rural South to urban North and West between 1910s and 1940s threw the distinction between black and white into sharper relief.

The involvement of African Americans in World War II also caused a major shift in racial issues on the home front. The dissonance African Americans experienced between fighting for democracy abroad but being denied its benefits at home led to a surge in civil rights activism, particularly around segregation of the armed forces and the defense industries. As segregation (also known as "Jim Crow") became the central American racial issue, racial differences among whites became less important. By emphasizing the black/white binary, Jim Crow could work to solidfy the whiteness of certain groups, such as Jews, who had previously been considered ambiguously white. Finally, Nazi Germany served as a sharp reminder of the horrific dangers of race-based classifications.

After World War II, Jewishness remained a social distinction but no longer a racial one. For example, Jews were allowed to move into white suburban neighborhoods that the Federal Housing Authority policy determined were only for people of the "same social and racial classes" (though some communities instituted housing covenants that excluded Jews). "Ethnicity" became the new language to describe difference among whites, now seen as cultural – a distinction that further entrenched the black/white divide by implying that racial differences go deeper than cultural differences. The new racial system defined whiteness as the "normal" American state, and blackness as a racial problem.

Many scholars have argued that Jews in the South were the first Jews to see themselves as white, but the case of Leo Frank makes clear that they occupied an ambiguous middle category of racial outsider. In April 1913, a 14-year-old white girl was murdered in a pencil factory in Atlanta, and Leo Frank, a Jewish part-owner and manager of the factory, was convicted of the crime based on the testimony of a black janitor. When his sentence was commuted by the Governor in August 1915, a mob pulled him out of the prison where he was being held and lynched him. That a supposedly white man could be convicted based on the testimony of a black man, and the use of lynching as the method of (illegally) meting out his punishment, demonstrates the contingency of Frank's perceived whiteness.

Throughout the postwar period, the social position of Jews in the South was precarious, despite the fact that Southern Jews were among those Jews with the longest roots in the US. Jews in the South were accepted as part of the social fabric, and in many cities were prominent business people who often ran the local store, but they were also seen as different from other whites and somewhat suspect, and in some cases excluded along with blacks. They had to work hard to fit in, and many Jews were reluctant to take action that would set them apart from the other white community leaders. They felt they needed to assure their own equality and security first, and therefore were often hesitant to engage in overt, public civil rights activism, though some supported civil rights in quiet, private ways.

While for some Southern Jews, association with the Civil Rights Movement confirmed for their white neighbors a lingering sense that Jews were racially tainted, for many Northern Jews, involvement in the Civil Rights Movement served to further solidify Jewish whiteness. Allying themselves with blacks cast into sharper relief the whiteness of Jews – ironically, since many Jews were motivated to civil rights activism by a sense of identification with African Americans and a persistent sense of "otherness" despite having, by and large, "made it" in America.

Today, many American Jews retain an ambivalence about whiteness, despite the fact that the vast majority have benefited and continue to benefit from white privilege. This ambivalence stems from many different places: a deep connection to a Jewish history of discrimination and otherness; a moral imperative to identify with the stranger; an anti-universalist impulse that does not want Jews to be among the "melted" in the proverbial melting pot; an experience of prejudice and awareness of the contingency of whiteness; a feeling that Jewish identity is not fully described by religion but has some ethnic/tribal component that feels more accurately described by race; and a discomfort with contemporary Jewish power and privilege.

And of course, while there is a tendency in the US, where the majority of Jews are of Eastern European descent, to assume a shared white racial identity for Jews, many Jews are in fact not white. Throughout history, Jews have come in all colors and from all places, and have almost always lived multicultural lives. The "mixed multitude" of the Jewish people include Jews from Arab lands (Mizrahi Jews), Jews with roots in Spain and Portugal (Sephardic Jews), and Jews from India, Asia, and Africa, some of whose ancestors may have been separated from the rest of the Jewish community many centuries ago. There are many Jews of color whose families have been Jewish for generations, if not centuries. In an American context that increasingly values diversity, the backgrounds and colors of the Jewish community are also enriched by adoption, intermarriage, and conversion. The Institute for Jewish and Community Research, an organization that studies the demography of the Jewish people, estimates that at least 20% of the American Jewish population is what they term "racially and ethnically diverse, including African, African American, Latino (Hispanic), Asian, Native American, Sephardic, Mizrahi and mixed-race Jews by heritage, adoption, and marriage."

Just as the definition of racial categories in America is always shifting, as illustrated by changes in the options for racial self-definition on the US Census, so, too, does the definition of Jewish identity and the image of what Jewish looks like continue to change.