Latter-day Saints (including me) in the 21st century have, to say the least, a complex relationship with their past. A friend once told me that Mormon history offers everything a historian could ask for—polygamy, visions, ancient books, violence, prophets, etc. While these things fascinate historians and buffs alike, for many contemporary Mormons that are missionary minded, they present uncomfortable difficulties when brought up with friends of other faiths. I think that part of this discomfort stems from the fact that we no longer see ourselves in parts of our past. When we share stories about ourselves with others, we choose aspects of our past that we feel define us. In like manner, we hide or diminish those things that embarrass us. One of these things is Joseph Smith’s practice of polygamy.
For much of the 19th century and even during the first decades of the 20th century, this was not the case. As SC Taysom has shown, once the Saints publicly announced that plural marriage was a religious tenet in 1852, telling the world that Joseph Smith was a polygamist was an integral part of Mormon self-representations.  These self-representations were soon contested however by the counter-memory put forward by members of the Reorganized Church of Jesus Christ of Latter Day Saints–a counter-narrative that portrayed Smith as a monogamist. Debates with the RLDS became a struggle over who would have the power to define Smith’s image in the wider culture and, by extension, the power to claim the mantle of Joseph Smith’s Mormonism. Embracing the memory of Smith as a polygamist was therefore an integral part of Brighamite identity during the 19th century.
The complete abandonment of polygamy in the first decades of the 20th century, coupled with changing relations with the RLDS, has moved Smith’s polygamy from the center of our public self-representations to the margins. At times, it seems that his polygamy is only in the picture when we’re called upon to defend him. Smith’s polygamy is now an embarrassment to modern Mormons, and remembering his polygamy is usually avoided (or diminished) in public representations of our past. Perhaps most ironically and tragically, I’ve observed that many disaffected Mormons claim that learning about Joseph Smith’s polygamy–primarily polyandry and marrying 14-year-old girls–contributed to their becoming disillusioned. What was once a bulwark of Mormon identity now serves in some cases to contest and even disintegrate it.
Note: To be clear, since there seems to be some confusion, I am not saying that most Mormons in their private lives or in their discussions among themselves, are embarrassed by Smith’s polygamy. Rather, I am pointing to embarrassment in their self-representations to others outside of the faith.
 Stephen C. Taysom, “A Uniform and Common Recollection: Joseph Smith’s Legacy, Polygamy, and the Creation of Mormon Public Memory, 1852-2002,” Dialogue 35, no. 3 (Fall 2002): 114-44.