Rabbi Morris Raphall went to Congress to defend slavery in an address on the House floor, IIRC. He was rabbi of Bnai Jeshurun on the UWS back when it was a traditional congregation, as opposed to the Reform-Conservative hybrid it is nowadays.
Rabbi Sabato Morais embodied the Sephardic tradition of Religious Humanism to the fullest extent. Thinkers such as R’ Morais, H’ David Nieto, R’ Moses Angel, Sra. Grace Aguilar, R’ Yisrael Moshe Hazzan, R’ Yaakov Moshe Toledano, H’ Benzion Uziel, R’ Eliyahu Benamozegh, H’ Moshe Halfon haKohen, etc. represent the best of the Neo-Classical Sephardic tradition, and these rabbis engaged the world and critical thought in a way that would make many Orthodox Jews very uncomfortable nowadays (and they lived years ago).