Reporting for this piece was supported by the Pulitzer Center.Right now, it can seem almost comically difficult to be Jewish. We’ve seen worse times, obviously, but the last year has brought us murders in Pittsburgh and in Poway, Cal., a substantial spike in anti-Semitic graffiti and hate crimes, and a painful internal debate about new members of Congress who seem, to many of us, anti-Semitic. Meanwhile, Jewish literacy is paltry, and birth and marriage rates are, except in the Orthodox community, low. In such a time as this, Judaism can feel like a fraternity nobody would ever want to join. Some of us were born into it, and we’re glad. But why would anyone else want to go through the rush process?It may seem surprising, then, but conversion—born of the desires of thousands of people to become Jews—has become the fierce battleground joining Reform, Conservative and Orthodox Jews today, in the United States and in Israel. Orthodox Jewry won’t recognize non-Orthodox conversions, the Israeli rabbinate won’t recognize conversions done by some American Orthodox rabbis. Converts everywhere face discrimination, like comments from fellow Jews that they aren’t “really Jewish.” Instead of welcoming new Jews from every possible quarter, we have made a mess of how we treat aspiring Jews, even as we need them more than ever.How did it come to this, that a people in demographic—and other—danger is mucking up the process of accepting new members? The simple answer is that we have lost their unique sense of how one might become a new Jew. In its biblical origins, conversion emphasized piety and family loyalty, but it has become a bureaucratic, and often anti-spiritual, morass. Jews are not alone here: Roman Catholics and many Protestants have also made conversion more complicated; all faiths are coping with the increased legalism of contemporary life. But for Jews in particular, the checklist mentality, endemic to modern life, is a particularly unfaithful way to look at conversion.As it happens, this Saturday night begins the Jewish holiday of Shavuot, a traditional time for those studying for conversion to complete the process by immersing in the ritual bath. On Shavuot, synagogues read aloud the Book of Ruth, about a convert who became, according to Torah, the foremother of King David and someday, Jews believe, the Messiah himself. After her Jewish husband’s death, Ruth stayed with her mother-in-law, Naomi, saying: “Wherever you go, I will go … your people shall be my people, and your God my God.”Ruth is a Moabite, and the biblical Moabites were much disdained by Jews, descended of the incestuous relationship between Lot and his daughter. An impoverished Moabite widow is thus the ultimate outsider—and yet Ruth joins, and renews, the troubled Israelite tribe. She becomes the quintessential ger, Hebrew for both “stranger” and “convert.” The convert is the stranger who comes to remind us who we are, and becomes one of us, maybe the best of us.Initially, then, one became a Jew by traveling with us, throwing in your lot with us. Yet in Talmudic times, the first few hundred years of the common era, Jews jettisoned this beautifully simple paradigm in favor of a system, presided over by male rabbis, that has grown more elaborate with time. First, an aspiring convert is turned away. If she persists, she must take classes, learn elements of a foreign language (with a foreign alphabet), study Jewish law and practice, and try to figure out this weird path that is a religion and a culture and an ethnicity and a family, all at once. Then she goes before a tribunal of three rabbis, who quiz her (some batei din, or rabbinic courts, ask for a written conversion statement, like a term paper but with higher stakes). Then she immerses in a mikveh, a ritual bath.It’s not that the process doesn’t work. For thousands of potential Jews at any time, it does. Conversion programs are flourishing: in Pittsburgh, Los Angeles, Tel Aviv, all over. At the Center for Exploring Judaism, at Manhattan’s Central Synagogue, about 75 non-Jews begin studying Judaism every year, three quarters of whom end up converting, according to Rabbi Lisa Rubin—and that’s one synagogue on an island with many. I meet conversion students everywhere. These women, men and children—in Savannah, Ga., a 13-year-old girl converted last year—emerge more knowledgeable than Jews by birth, and they often say that the rigorrous process, makes eventually becoming a Jew all the more meaningful.Still, with every additional step, controversy can insert itself. One rabbinic court can dispute the conversions of another, or, alas, rabbis can abuse potential converts, demanding steep payments, or worse (consider the Orthodox rabbi Barry Freundel, who spied on naked women immersing in the mikveh). Ruth and Naomi would have recognized none of this.Historically, of course, there was good reason for barriers to conversion. In Russia, Prussia and elsewhere, it was illegal for Christians to convert to Judaism, or for Jews to seek converts (contrary to myth, Jews have no theological objection to proselytizing; we just stopped doing it where it got us killed). Persecution made Jews wary of outsiders, and any Christian who sought to be Jewish could well be suspected of being a spy, or crazy, or both. Catholics, for their part, were happy to do quickie conversions—but in Jews’ experiences, these were often baptisms at sword-point.So Jews continued their practice of matrilineal descent, and made it hard for anyone to convert in. In recent centuries, Jews have layered on aspects of Christendom: instead of a baptismal certificate, a Jew gets a conversion certificate. And informal study with a rabbi has been replaced by classes with routinized curricula, some of them even taught online. Meanwhile, Catholic conversion, once a matter only of baptism, has also evolved. After Constantine, rulers who converted just declared their subjects Catholic, making individual baptism less important. Missionaries called many native people Catholic, some of whom wanted to be, some of whom didn’t. Only in 1972 did the Church arrived at the requirement that adult converts must take instruction.Every tradition has to find its way. For Catholics and high-church Protestants, required study is a hedge against the forced conversion of the crusades and colonialism, on the one hand, and what they take to be the shallow enthusiasm of born-again evangelicalism. Although some Hindu sects have tried to standardize conversion, for others, Hinduism is a way of life anyone can follow; still others argue that non-Hindus, who can’t be placed in the caste system so integral to Hinduism, can never really belong. To become a Muslim, one need only recite the Shahada, the seven-word creed; such an easy on-ramp would never make sense for Judaism, which is conceived as an extended family rather than a universal calling, but it works for Islam.Unfortunately, we’ve lost sight of what works for Judaism. Our strict binary is doomed to fail. Either one must be born of a Jewish mother (Reform Jews would say father, too, a recent innovation), or one must study for conversion. This practice of privileging matrilineal descent, and forcing everyone else to the conversion courts, may hoist us all on the petards of our DNA, as all of us, from the secular to the most Orthodox, can now discover that, by traditional standards, we’re not Jewish. All it takes is for a mother’s mother’s mother’s mother’s mother (and onward; you get the idea) to have not been Jewish, and the whole line is not. How many of us will pass a purity test going back to Mount Sinai?But most important, as current events remind us, there are more meaningful, more essential, tests of who is truly a Jew. To focus on DNA or conversion courts misses the point. Since the deadly attack on the Tree of Life synagogue in Pittsburgh last October 27, I have been traveling weekly to the Squirrel Hill neighborhood, interviewing survivors, victims’ families, and dozens of other local Jews and Gentiles. And I have seen that Jews by choice (as converts sometimes call themselves) are central to every aspect of this story.One of the Jews who was shot but survived is an adult convert—and is also a past president of one of the three congregations housed in the Tree of Life building. All three congregations have numerous converts among their membership. The chair of adult learning at a large Conservative synagogue in Squirrel Hill, one where the displaced members of one of the attacked congregations now meet, is a convert.And in the days after the shooting, converts were involved—quietly, without anyone noticing who’s a convert and who isn’t—in the rituals of burial and grieving. One of the two chevrei kedisha, the Jewish burial societies that wash and prepare bodies for interment, counts several converts in its membership. One member of that chevra kedisha, somebody who has cleaned numerous dead Jewish bodies—removed rings from fingers, cleaned under fingernails, ritually poured water over them, dressed them in linen shrouds, all while intoning prayers—told me that her mother’s father was Jewish, but not her mother’s mother. Although Jewish by Reform standards, she is now studying for conversion.But if she can clean a martyred Jewish body, isn’t that enough? Ruth’s conversion was just her pledge to stick with her late husband’s family. Moses’ wife, Zipporah, never took classes at the JCC or the synagogue’s adult-education center: she married Moses, raised his children, even circumcised one of their sons when Moses didn’t. They were Jews because they lived as Jews.Today, right now, thousands have committed to the Jewish way of life without formally converting. They’re just jewing it, as one friend of mine puts it. In my synagogue, there are non-Jewish spouses who prepare our Saturday communal lunch, lead children’s services, visit the sick and elderly, cook meals for new parents, and know more Hebrew and Jewish customs than many of us born Jewish. And insofar as showing up at synagogue on Friday night or Saturday or sending one’s children to Hebrew school can feel like risky acts, they are profoundly Jewish acts—no matter who does them. Today, as in biblical times, to travel with us Jews feels like statement enough.Does that mean religions should have no formal conversion process? Not quite. Judaism, after all, is based on the idea of extended kinship, and being welcomed into a family requires evidence of one’s commitment. And we are right to be suspicious of those who claim, or discover, their Jewish identity only when it’s politically convenient, as when they want to make a point about Israel.But if we need fences around our community, they still have to be the right kind. The discussion about who has a Jewish neshama, soul, needs to move beyond debates about bloodline purity and the stringency of conversion processes. It’s worth considering that accepting simple declarations of conversion does not seem to have weakened Islam, or evangelical Christianity. Maybe Jews have our own version of a simple test need: to ask what makes someone Ruth-like.In the Book of Ruth, after Naomi’s two sons die, she tells her daughter-in-law, Ruth and Orpah, to leave her. “Turn back, each of you to her mother’s house,” she says, kissing them. The daughters weep, and Orpah agrees to leave. Naomi tells Ruth that she, too, should go. “Go follow your sister-in-law,” she says. But Ruth refuses. She will go where Naomi goes, sleep where she sleeps. “Where you die, I will die, and there I will be buried.” Since this book was last read in synagogue, eleven of us died in Pittsburgh. Then another in Poway, Cal. They are buried in Jewish cemeteries. Whoever is willing to live with us, and then be buried with us—isn’t he a Jew, too?