The religious are often led and inspired by the words and deeds of the dead: Abraham, Moses, Jesus Christ, Mohammed. Within the Jewish realm, the list of great, late leaders includes the sages of the Babylonian Talmud, the Geonim ("the geniuses," 7th- to 11th-century scholars), the Rishonim ("the first ones," 11th- to 16th-century rabbis), or the Achronim ("the last ones," rabbis from the 17th century and on). All were great scholars, admired by many; all were religious leaders of their respective places and times who continue to guide the faithful.
Some of them were also admired communal rabbis, of the kind many American Jews will shortly meet on High Holidays services; for many attendees, this will be the annual encounter with their rabbi. But they were also much more. The Jewish world of the 21st century has very few, if any, rabbis and scholars universally accepted as "great" or "sagely" who are admired even by those outside the specific sect, stream, or group on which the rabbi in question presides. Jewish communities around the world have been unable to find suitable successors to those "last ones." The problem is particularly manifest within the American Jewish community.
This is a relatively new and perplexing phenomenon, and it's difficult to pinpoint why great American rabbis seem to be a thing of the past. Within Jewish tradition, the thesis of the "decline of the generations" (in Hebrew: Yeridat Ha'Dorot) is a very prevalent one, inversely related to the distance from Sinai. Is what we see in America today proof of this thesis (though not all great Jewish thinkers accept it)? Is it a problem with today's rabbis, students, and scholars? Are we in the early years of a drought in Jewish thought? Or maybe the problem is not the rabbis but rather the changing times and changing nature of Judaism, which makes it more difficult for anyone to acquire greatness.
The crisis is widely evident, as those following the Hasidic communities in the United States can attest. The Lubavitcher Rebbe is gone for 16 years, but no successor of similar greatness was taking over the Chabad Hasidic community. The Satmar Hasidim weren't able to agree on one leader; the Bobov Hasidim had a similar problem that required court involvement. Instead of one great leader, each sect settled for a couple of "smaller" ones. No rabbi was great enough to occupy the place of Joseph Dov Soloveichik in the minds and hearts of modern-Orthodox Jews after his passing in the early '90s. No one was authoritative enough to be the agreed-upon heir to ultra-Orthodox Rabbi Moshe Feinstein, who passed away in the mid-'80s. And more progressive streams of Judaism have encountered this problem as well: Abraham Joshua Heschel has had no successor since his departure in the early '70s. Mordechai Kaplan, the founder of Reconstructionist Judaism, had fame that no contemporary rabbi can compete with.
What these great men of the past had in common was a community that was more interested in group identity and much more attentive to the teachings of rabbis. (They all came to the New World from Europe, though Kaplan did so at a very early age.)
Today, Jewish religious life is guided by organizational wizards—not men of spiritual wisdom. Newsweek's somewhat idiotic yearly list of "50 most influential rabbis" was topped in 2010 by Rabbi Yehuda Karinsky, the leader the of Chabad-Lubavitch movement. Following him were Rabbi Eric Yoffie, the president of the Reform Movement, and Rabbi Marvin Hier, the founder of the Simon Wiesenthal Center. I have many friends on this list and do not wish to offend them, but my assumption is that all three, and most of the other 47 picks, were selected for worldly, not spiritual, reasons: because of organizational significance (Yehiel Eckstein), political work (David Saperstein), celebrity (Shmuley Boteach), high-profile battles (Sara Hurwitz, "the first female Orthodox rabbi"), or leading unique communities (Sharon Braus, the award-winning rabbi of the innovative IKAR Synagogue). None has the sagely status of some rabbis of previous generations.
The list includes some important scholars, but most of them are just, well, scholars. They have knowledge, they have gravitas, but most do not have "followers" in the traditional religious meaning. And those who do have followers are more often of a New Agey bent, like Rabbi Yehuda Berg of the Kabbalah Center, spiritual home of Madonna. Rabbi Zalman Schachter-Shalomi, the founder of Jewish Renewal, might be one example of someone with both followers and new ideas and real long-term influence on American Jewish religious life. But guess what? He was born in Poland. If one will consider him "great," one must wonder why greatness is almost never homegrown American.