“Your post documents a number of cases where the Mormon prophets held to a doctrine as long as it was not politically unpopular (slavery, polygamy, inferiority of blacks).”
The church was never in support of slavery. Part of the reason they were persecuted in some areas was because they were against it.
The church also endured a great deal of hardship and persecution at the hands of the US Government and others over it’s practice of polygamy and it was willing to continue doing so if that was God’s will. Just because you see a practical reason for something doesn’t mean that it was not commanded by God, and even before they started practicing it the BoM was clear that there were times it was apporved and times it was forbidden.
It was never the position of the church that blacks were inferior, only that they were not permitted to hold the priesthood at that time, something that has historical precedent in the Bible with the preisthood being limited to only the Levites. Brigham Young also said way back then that a day would come when the ban would be ended, clearly indicating it was a temporary thing.
If it was based on blacks being inferior, why would it be temporary? If it was ended today instead of in 1978, or any day after today, would you see it as being any less poll driven? The only way to appear not poll driven would be to make it permanent, but that would be contrary to what we know God wanted, and we knew that before there were polls.
“Because I reject that faith does not mean I hold any animus against Mormons personally or as political candidates. I would vote for Mitt over a Democrat without a second’s hesitation.”
That’s fine. People should look at relevant factors like experience, record, platform, qualifications etc. instead of basing their decision on religious differences that really won’t have any impact on how they would preform their duties.