Reform movement
B'nai Jeshurun took a leading role in founding the Board of Directors of American Israelites in 1859. By 1874, there were divisions within the congregation over remaining strictly Orthodox or adopting ideas from the Reform movement, and by 1875, it was in litigation, with the Reform movement ultimately winning in court. The Board of Delegates affiliated with the Reform movement's Union of American Hebrew Congregations in 1878, but in 1884 it left. Two years later, it also supported the founding of the Jewish Theological Seminary of America (JTS) in 1886, a school formed to support Orthodoxy in combating the Reform movement.