This is the all-star game of polygamy debates, folks. Orson Pratt was Brigham Young’s point man for explaining and defending polygamy, and the Rev. Dr. J. P. Newman, Chaplain of the U. S. Senate, sounds like a worthy opponent. In 1870 they publicly debated the question “Does the Bible sanction Polygamy?” for three days, and that debate is reproduced in The Bible and Polygamy, now available free on Project Gutenberg. It also includes discourses on polygamy by George A. Smith, George Q. Cannon, and Pratt himself. It’s thus a cross-section of both Mormon and non-Mormon thought on polygamy in the middle of the pre-Manifesto Utah period. Have a look.