By the numbers, Pew’s new U.S. Religious Landscape Study has pretty good news for Jews. While the country’s self-identified adult Christian population has dropped nearly eight percent and the Nones (those who identify with no religion) have risen by nearly seven percent since Pew’s last Landscape Study seven years ago, we are holding our own. Indeed, there’s even some indication of an uptick in the U.S. Jewish population, from 1.7 percent to 1.9 – the same as Pew reported in its 2013 “Portrait of Jewish Americans.”

That said, there’s no reason to stop worrying about Jewish continuity. On the contrary, the larger shift away from religious identification in American society poses a particular challenge to our community. In order to understand why, you have to understand who the Nones are and why their proportion of the U.S. adult populations has tripled from seven percent to more than 21 percent over the past quarter-century.

Nones are people who when asked what their religion is answer, “None.” That doesn’t necessarily mean they disbelieve in God or lack a spiritual life. What they’re doing is answering a question about personal identity, as in: What is your nationality? Or, what is your race? Or, what is your sexual preference? Nones are people who choose not to make a religion part of their identity.

In the United States, there are two ways that you can come to have a religious identity: by ascription or by choice. Thus you can become a Jew by having a Jewish mother or in Reform Judaism a Jewish father (ascription), or by converting to Judaism (choice). Most religious traditions provide for both approaches, though to varying degrees. While Baptists restrict church membership to those who make a choice for Christ by having themselves baptized, the fact is that unbaptized children who grow up in Baptist families come to think of themselves as Baptists, and in due course are more likely than anyone else to make the choice to become a Baptist.

The reason that the percentage of Nones has risen as steeply as it has is that since 1990 Americans have come to understand the question of religious identity as being more about choice than ascription. Thirty years ago, someone who was sent to a Presbyterian Sunday School as a child but who has not darkened a church door in years could well have  answered the “what is your religion” question with “Presbyterian.” Now, she is more likely to say, “None.”

What this means is that today, a shrinking proportion of Americans are “nominal” religious identifiers in the strict sense of the word “nominal”: They’re less likely to identify themselves with the name of the religious tradition they were raised in if their only current connection to the tradition is that they happened to be raised in it. And this goes for Americans of all faith traditions, of all ethnicities, in all parts of the country – including Jews.

Increasingly, then, we are all Jews by choice. As a community concerned about its future, we cannot assume, as we assumed in the past, that the vast majority of those born into Jewish families would identify as Jews for as long as they lived, whether or not they observed mitzvot and belonged to a synagogue. To put it bluntly, birthright matters less to American Jews today than what is meaningful religiously and culturally to them at the present time. No longer can Jewish institutions depend on ascribed Jewish identity alone to provide the underpinnings of communal support. American Jews have to be provided with reasons for choosing a Jewish identity, and not just at one age or another, but continuously, to keep on choosing it. n