Utah had a big problem joining the Union, big love. The presence of polygamy hampered the Utah territory's ability to join the Union. It was not until the Federal Government enacted a serious of coercive actions that the territory officially gave up the practice, but, depending on who you read, not necessarily the religious importance of polygamy: the GOP organized to remove "the twin relics of barbarism," slavery and polygamy; Buchanan marched troops into Utah in 1857, an act some have called the first Civil War; the Edmunds Act and the bi-sectional (North and South) Edmunds-Tucker Act. Despite coercive pressure, polygamy still lingered amongst several high ranking members of the Latter-day Saints, as the seating of Senator Smoot evinced. In a bit of historical irony, Smoot was a Republican. Additionally, polygamy lingered on as the LDS suffered from a serious of schism, most notably Fundamentalist Church of Jesus Christ of Latter-day Saints.

By pre-civil war states are you referring to all states that entered the Union from Independence until 1865, or simply those states admitted after 1844 or 1848?