White Horse Prophecy [View all]
Having seen several references on the internets to a Mormon prophecy of an LDS president, I googled around some. I think the "presidential prophecy" thing is a (somewhat distorted) take on the "White Horse Prophecy," which is something Joseph Smith is purported to have said in 1843.
Essentially, that one day the US Constitution would hang by a thread and the Mormon Elders would have to save it. I don't know that there was an explicit prophecy of an LDS president.
The current LDS church does not favor the White Horse prophecy, and some say it was never made. It was, however, taken seriously by a lot of major LDS figures at times, including Brigham Young.
This is my personal observationFamous prophecies are often about things long past. It is important to note that in 1843 the US Constitution was already hanging by a thread. (Which would all but snap 17 years later) It was no secret the the United States was in danger of eventual dissolution over slavery. As to what the LDS elders would have done to resolve the slavery issue that was, at the time, endangering the Union, I do not know. But if Smith made the prophecy it's a good bet he wasn't thinking about 2012.
Mitt Romney has said he considers the White Horse Prophecy to be a matter of "speculation and discussion by [LDS] church members" and "not official [LDS] church doctrine."
As interpreted through the years, it has a very Tea Party ring to it:
In 1928, the LDS apostle Melvin J. Ballard remarked that "the prophet Joseph Smith said the time will come when, through secret organizations taking the law into their own hands ... the Constitution of the United States would be so torn and rent asunder, and life and property and peace and security would be held of so little value, that the Constitution would, as it were, hang by a thread. This Constitution will be preserved, but it will be preserved very largely in consequence of what the Lord has revealed and what [the Mormons], through listening to the Lord and being obedient, will help to bring about, to stabilize and give permanency and effect to the Constitution itself. That also is our mission."
http://en.wikipedia.org/wiki/White_Horse_Prophecy#United_States_Constitution