Louis Brandeis was a descendant of one of the prominent Shabbatean/Frankist families of Prague. They did not follow Frank’s example of conversion to Islam or Catholicism, but maintained a Jewish identity, though very detached from Jewish ritual and practice. His mother Frederika Dembitz Goldmark Brandeis “disdained formal religious ceremonies and encouraged her children to value ethical teachings of religion, including Judaism, while eschewing the age-old rituals.” Brandeis grew up in the family environment, where, though born a Jew, he was not raised as a Jew. In fact, he celebrated Christmas, but not the Jewish holidays; neither did he keep the kosher laws, or the sabbath. He was very disengaged from Jewish practice.
Brandeis’s maternal uncle, Gottlieb Wehle, wrote an ethical will in which he exhorts members of his family to “respect their ancestors’ tradition of antinomian disdain for the normative Judaism of traditional rabbis.” This was perhaps a reaction to the family’s waning allegiance to the Frank sect. It was Justice Brandeis’s relatives, who revealed a copy of a portion of this will to Gershom scholem, who published it. In fact, Brandeis manifested a great interest in his mother’s background as evidenced by his insistence that she write down the history of the family, which she did. Although she never clearly expressed her Frankist background, she did allude to it. In her letters she gives some insight into why Louis Brandeis was so divorced from traditional Judaism. The environment as presented in her letters in which she detailed her family background evinces an anti-traditional atmosphere. It harkened back to a time in Prague when it was normative to be Jewish ethnically, German culturally, and Austrian politically. Yet, the Brandeis family, obviously influenced by the Frankist sect, had shunned their Jewishness and failed to expose their son Louis to anything more than the vagaries of Jewish identity.
Brandeis’s mother gave him a copy of a picture of Eva Frank (who was Jacob Frank’s daughter and his spiritual successor upon his death), which was handed down and reserved for those who were privileged descendants of Frankists. This generation of Frankists had thrown off and/or forgotten the deviant ways of the founder; previous generations had actually destroyed the written remnants of their affiliation with the sect, even going door to door to collect any memoirs or written traces of the sect, so that they could discard the embarrassing “evidence.” They continued, however, to maintain a certain elitist pride about being connected to the sect’s past. This pride was reflected in Brandeis’s mother’s letters to her son; her descriptions of the close-knit community bespeak the Frankist sect in clandestine terms. Hence, we know that Louis Brandeis knew of this “ghost in the closet,” that would not be wise to profess openly. This may have made him particularly sensitive about the importance of the right to privacy (which he defined in his co-authored Right to Privacy article as the right to an “inviolate personality”) and the right to speak one’s conscience.
Louis Brandeis took his second cousin, Alice, as his bride, a practice not uncommon for Jewish people and Frankists during this era. she too was a descendant of the circle of Crypto-Frankist Jews, and was undoubtedly aware of the secret of the family’s past.
Brandeis' Frankist roots might explain his distance from anything Jewish until relatively late in his life. Only at age 56, in the year 1912 did he become active in the Zionist arena, probably as a conscious response to the Pogroms in Eastern Europe. He was very active for the next few years only to back off in 1919 after breaking off with Chaim Weizmann.
How many other Frankists are still among us, we may never know, and how much Frank had an effect on the abandonment of Jewish Traditions by the vast majority of today's Jews will probably remain a Mystery. On the other extreme of Judaism, Prof. Immanuel Etkes of Hebrew University says, "No doubt the Vilna Gaon suspected that the Hassidim were a sect like the Frankists".
If you are in to conspiracies, there is much more. It seems there are all-conspiracy-believing anti-Semites who believe that Frankists are still around today under a different name. Here is a quote from one of their sites "The Frankists today no longer call themselves by that name. The Organization has grown into an international group labeled by outsiders as the Cult of the All-Seeing Eye". While we are at it, Barry Chamish, an Israeli author, whom some might know from his work trying to prove that Yitzchak Rabin was not killed by Yigal Amir states "The initial financiers of Labor Zionism and Theodore Herzl were barons of the Rothschild clan. Their goal was the creation of a state in the image of their Sabbatean/Frankist beliefs: that is, anti-Torah, anti-Talmudic, anti-religious and anti-Jewish". Pretty much any Jew in a power of authority in the last few hundred years has been or is accused by one nut or another of being a Frankist, who knows, perhaps in a few instances they are right.