One of the few cultural institutions to hold over from the old United States was the Church of Latter Days Saints. In Industrial times, its members were instructed to keep stores of food in case of disaster, and even the Church itself had supplies of grain on hand. When disaster did indeed turn out to strike, the preparations and rigid structure of the Mormons allowed them to ride the storm out with a relative lack of problems also helping out was the Mormon epicenter, Utah, being sandwiched between mountains and barren desert. This not only create buffer from sieges, but it allowed the non-Mormons to either be weeded out or quickly kowtow to spiritual salvation in order to secure earthly salvation.
With most of the population already leaning this way, and power over things like food and water in these times of strife, the Church of Latter Day Saints transitioned from a de facto theocracy to an active one. It was from here a Hydraulic Empire was secured, and the Church became one with the Empire of Deseret. Even in more secular times, much of its members' daily lives revolved around the church and its very rigid structure, so it was not too hard to flex its power a little more. Mormon congregations, called Wards, play an active role in every day life. Even courting between young singles is pretty much instructed by the Wards. Elite and middle class families are often enlisted to do the Church's work for a period of time, maybe even years. Peasant families' involvement varies more, as not to disrupt the growing season, but children may often be drafted to fill the ranks of soldiers, bureaucrats or concubines. Still, any Mormon is expected to serve the Church at the drop of a hat.
Through much of the millennia, Mormonism has changed little. Tobacco and liquor are outlawed, though the more fiscally-minded governors have allowed trade to pass through the borders. The book of Mormon is taken more seriously than ever, and theological history the places the faith in the continent give Mormons a sense that it is the true faith of America. (Of course, other religions feel that way, this is just their argument) Multiple wives have been allowed again, due to the wish to populate the basin and new colonies as much as possible, as well as the lecherous intents of previous Governors. It also helped that the mainstream Church absorbed a few fringe groups. With the United States no longer a concern, the offshoot compounds were not a major concern, though leadership was eventually supplanted with the President's family.
The President is voted on by the ruling family, which can often be quite numerous. The most powerful twelve are the elders, and although they play a significant role in theory, power-hungry Presidents are not always comfortable with the politicking and backstabbing that can take place. As a result, they may kick contentious Elders upstairs to distant states. Most of their advice are taken from loyal Eunuchs, who they refer to as counselors.
Colonies are a major part of the Mormon manifest. After all, the desert can only support so much life, and the Church very much means to convert the world. Therefore, missions, which were very peaceful in Industrial times, are now extremely warlike. The President's army consists mounted knights known as Templars, who are instructed to sway or slay the native heretics. These newly conquered areas are known as Stakes, territories from which to spread the book of Mormon. This usually results most of the males being taken out and the females becoming wives to form a new Stake community.
Our in the East, the Non_Denominational Church does not have much a relationship with the Mormons, but refers to the Church as "The Temple".