Rabbi Menachem Mendel Schneerson, left, in 1993. Photographer: Shahar Azran/AFP/Getty Images
Rabbi Menachem Mendel Schneerson, left, in 1993. Photographer: Shahar Azran/AFP/Getty Images

(Corrects anniversary date of Rabbi Schneerson's death in first paragraph.)

Rabbi Menachem Mendel Schneerson, who by the Jewish calendar died 20 years ago a week from today, was easily the most important rabbi of the second half of the 20th century in the U.S. At his death, his legacy was uncertain: He left no successor, and his followers, the Chabad Lubavitch Hasidim, found themselves locked in a profound internal dispute about whether the man they expected to be revealed as the messiah had in fact died with the world unredeemed.

Today, it’s possible to begin writing the second draft of the history of the man who came to be known simply as “the Rebbe”: Despite his European origins, Schneerson was the quintessential American rabbi, one who transformed U.S. ultra-Orthodoxy from inward looking to outreach focused. His philosophy of openness to all Jews, regardless of religious orientation, has had a huge impact throughout Jewish orthodoxy and beyond. And his messianism, far from sinking his movement, has enabled its emissaries around the globe to continue his mission unabated.

Schneerson had an unusual -- and unusually broad -- life trajectory before becoming the leader of the world’s largest Hasidic dynasty. Born in Russia into a family associated with the elite leadership of the movement, Schneerson married the sixth grand rabbi’s daughter. Trained as an engineer in Paris and Berlin and also steeped in rabbinical and mystical tradition, he succeeded as Rebbe only once in the U.S. after World War II.

It may be an exaggeration to argue, as the scholars Samuel Heilman and Menachem Friedman did in a 2012 book, that Schneerson expected to spend his life as an engineer. His connection to the leadership was too intimate for him not to have known that he might succeed to the throne. But there is no doubt that his exposure to the life of Western European capitals prepared him like no other Hasidic leader for the transition to American life.

Once he had assumed leadership, Schneerson began immediately in innumerable public lectures and private writings to develop an extraordinary religious philosophy. Steeped in Chabad Hasidism’s distinctive combination of Talmudic intellectualism and kabbalistic mysticism, his teachings were especially subtle and complex. At their core was the concept of what he called in Hebrew the “mamash,” which can very loosely be translated as “the actual” or “the concretely felt.” (The three letters of the Hebrew word also corresponded to Schneerson’s monogram, MMS.)

For Schneerson, the imperative of the actual demanded engagement with the real world as it actually existed. Since its inception in the 19th century, Jewish ultra-Orthodoxy had sought to separate the faithful from the modernizers who, they believed, threatened traditional Jewish life. Under Schneerson’s leadership, Chabad contradicted that paradigm. He personally sent emissaries to the four corners of the earth with instructions to set up shop and reach out to Jews who might have little or no religion in their lives. Instead of demanding total observance as the price of admission to Jewish communal life, as the ultra-Orthodox had done, the Chabad emissaries held out religious observance as an ideal to be sought after, and in the meantime accepted anyone who wanted to show up.

This unprecedented outreach, aimed at nonreligious Jews, reflected Schneerson’s growing messianic vision. The performance of divine commands would help bring about redemption. If all Jews would perform certain commandments as near in unison as possible, redemption might come more rapidly still. The Rebbe’s followers set up so-called mitzvah (commandment) tanks to disseminate the donning of tefillin, or phylacteries. They handed out gifts of food on the festival of Purim. And almost no public place in America is now bereft of a large Hanukkah menorah to be publicly lit by the local Chabad rabbi.

Never in world history had Jews asserted their religious practices so proudly and openly. Like the ambition and breadth of Chabad’s global missionizing, this was certainly a manifestation of the American spirit. Similarly, the project of inclusiveness -- coupled with a nonrelativistic commitment to religious truth -- resonated for American audiences.

Not all the American Jewish world embraced Chabad in Schneerson’s lifetime. Some Conservative and Reform Jews bristled at the movement’s rejection of religious pluralism and desire to change the worldviews of their movements’ members. Political liberals disliked Schneerson’s opposition to exchanging land for peace in Israel. Above all, ultra-Orthodox stalwarts were horrified as the Rebbe’s more enthusiastic followers began to declare that he was the messiah incarnate. Infirm and aged, the Rebbe took little visible action to restrain the enthusiasts -- and of course their belief was built on the devout messianism he had taught them.

When Schneerson died in 1994, the more extreme messianists among his followers surmised that he was in occultation, or perhaps would return in some noncorporeal form. Orthodox critics charged them with heresy and compared them to followers of other false messiahs, or even to Christians. For a time, the movement’s future within mainstream Orthodox Judaism was in question.

Yet remarkably, over the last two decades, instead of eschewing Chabad, the rest of ultra-Orthodoxy has begun to imitate them. Outreach to non-Orthodox Jews has become a growth industry, funded and pursued even by non-Hasidim who long rejected it as dangerous for internal solidarity. As the Rebbe had noticed before anyone else, in the U.S., reaching out didn’t need to threaten commitment within.

Chabad’s emissaries play important roles in the kosher food industry globally, certifying ingredients in places no other Orthodox rabbis are to be found -- and almost all Orthodox Jews are willing to rely on the certification. Fears of hidden, esoteric Chabad messianism persist in some Orthodox circles, but almost no one speaks about it publicly.

The Rebbe, in other words, triumphed. His followers have appointed no Rebbe to succeed him, because no one could, in their view, match his greatness. Yet his global movement flourishes, the result of a charisma that has been institutionalized through its emissaries. Chabad rabbis now serve as chief rabbis in eastern Europe and beyond, their position established by their early outreach. The next 20 years will open a new chapter in the life of Chabad. But one thing is sure: The movement will still be here, and the Rebbe’s teachings will actuate it.

To contact the writer of this article: Noah Feldman at noah_feldman@harvard.edu.

To contact the editor responsible for this article: Stacey Shick at sshick@bloomberg.net.