Comment: Some FYI on your concerns

The white horse prophecy is officially not official doctrine or canon of the LDS Church. Some members talk about it like it is, yes, and some even believe it, but that is just their individual opinion and belief and not that of the church. It stems from unsubstantiated and unverifiable reports and records from 2nd and 3rd parties that surfaced well after Joseph Smith's death and therefore can not be confirmed.

Some misinformed and unfortunately naive members of the church like to wiggle their eyebrows and go wink wink nudge nudge as if Romney is some how going to fulfill that prophecy but the truth is no one really knows if that prophecy is real, remembered or recorded correctly, or how exactly it will come to pass if at all.
It's basically hearsay that members of the church have been bringing up for the past 150 years or so any time some prominent LDS politician comes to power or is close to being elected.

Could it be true? Maybe, but there's no way to tell and no one would really know how it would come about anyway if it were true because that is not specified in the so called prophecy.

So what is true? Well I'm sure it is painfully obvious to everyone here that the constitution is in fact under attack and that it is being walked on and torn apart and in danger of being destroyed. What is true is that something needs to be done to defend and restore it. I do not believe that Romney is the one to do it barring some kind of sudden drastic Paul on the road to damascus conversion.

What is true is that Mormon's hold the constitution in high regard, or at least they should. The constitution is mentioned by name in official LDS scripture. We believe the Lord through revelation gave the church permission to befriend the constitution and said that the framers were inspired by him to write it in order to help protect the rights of the people and to be the law of the land. That honest wise and good leaders should be sought, and that when they are not sought the wicked rule and the people suffer. It is the obligation of Mormon people to uphold and defend the constitution and seek out good, honest and wise leaders. I face palm when I see many of them interpreting this as voting for Romney, as many of you do when you see family members or fellow republicans and conservatives planning on voting for him. So whether its elders of the church that somehow save the constitution or others, someone needs to do it.

As far as any take over conspiracy, yes there is one. But not like you're thinking. Mormon's are charged to bring the gospel of Jesus Christ, repentance and baptism to all the world. So yes we would like to convert the whole world if we could, if they so desire to be converted. As far as some kind of political take over and theocracy dictating Mormon morals on non mormons, no. I understand that is a legitimate concern of some not familiar with Mormonism, especially those who have lived in Utah, but no such political take over and dictatorship plan is in the works. The exercise of free will is a major part of Mormon theology. The denial of free will is believed to be the plan of satan. Such heavy handed tyranny is shunned and looked down upon as evil. Mormon's claim the privilege of worshiping Almighty God according to the dictates of theirr own conscience, and allow all men the same privilege, let them worship how, where, or what they may. They do not want to rule your life. And if they do they are in error.

As to the "I am a Mormon" ads, those are just the latest marketing campaign of Mormon ads that are part of the church's attempts to reach out and create more awareness of who Mormon's are and what they stand for. There have been Mormon ads for decades. If you look on youtube for 80's mormon ads you'll see some pretty cheesy yet good warm hearted ones about the family and doing the right thing. Kind of like public service messages but for the church. In fact this kind of advertising of the church through the media has been going on for a long time. Since July 15, 1929, the Mormon tabernacle choir has performed a weekly radio broadcast called Music and the Spoken Word, which is one of the longest-running continuous radio network broadcasts in the world. Mormon's are eager to get their message out any way they can. Are they interested in power and taking over the country or the world? No. They just want to raise their family and share the blessings of the gospel with others if they will let them. Forcing it on others is the last thing they want to do.

Finally, I lived in Provo too for years, lean libertarian and attended BYU in early 2000s. I'll admit at the time I wasn't fully aware what was going on, but I always held the constitution and the principles of freedom and liberty that it was supposed to enshrine and protect in high regard. Though I could never really find a politician in any party that really resonated with me that held the same views until I heard of Doctor Paul. That's when it really began to click for me and when I could finally put words and arguments behind the things I believed. and I'm not the only one. I was able to awaken many of my BYU friends too and I know there are many more out there that feel the same way about liberty in Utah.

TL;DR
-White horse prophecy is more of a myth and rumor than any kind of official doctrine and has been officially refused as such by the church
-Glen Beck's a looney and should not be taken seriously
-Mormon's are not trying to take over or create any kind of theocracy.
-Yes there may be some LDS members that think and believe the craziest theories and have delusions of power and grandeur just like anyone else or select few members of any other religion. They dont speak for the church.
-There are libertarian/Ron Paul/Constitutional people and LDS members in Utah. We could always use some more. The field is white and ready to harvest as the old saying goes. Looking forward to Ron Paul's visit and bringing some new friends to the rally who are interested in meeting him for the first time.