The “white horse prophecy” is a false prophecy by Joseph Smith when he was running for POTUS in 1844 that stated that the “Elders of Zion” (Mormons) would come in and rescue America when the constitution was “hanging by a thread”.
The prophecy also ties into their view that “one mighty and strong” will return. I suspect Romney sees himself as fulfilling both prophecies.
Some Mormons claim that this prophecy never happened and that the source are not reliable but LDS church owned museum has an official mural about the prophecy at the location where it was supposedly was given (Liberty Jail) and there is more than enough evidence to support the giving of the prophecy and the continued belief in it. When I lived in Utah in the early 1990’s it was common topic of conversation at BYU.
Recently, Rex Rammell in ID raise a fuss recently because he sent out invites to and LDS male only panel to discuss this prophecy.
http://www.ils.unc.edu/~unsworth/mormon/whitehorse.html
http://www.mrm.org/white-horse-prophecy
I used to be Mormon (convert). I left over 15 years ago and became a Christian.