I stated earlier how the Church gives the people of the world an ultimatum to accept everything it teaches as God's absolute truth, or to treat it as a fraud.
Each of us has to face the matter-either the Church is true, or it is a fraud. There is no middle ground. It is the Church and kingdom of God, or it is nothing. (Hinckley, 2003).An analogy for this ultimatum may compare the Church's doctrines to links in a chain.
The old saying goes, "A chain is only as strong as its weakest link." Once a single link in a chain breaks, the whole chain is unable to do what it is intended to do. It no longer functions. It doesn't matter how strong any other link in the chain is. All that matters is the weakest link.
Similarly, the truthfulness of the LDS church is dependent upon several "links". If any one of these links breaks, the only conclusion left is that the Church is not true. For example, if the Book of Mormon is not a record written by the prophets of the American Continent, then Joseph Smith must not have translated it from gold plates, and he couldn't, therefore, have done so by the power of God, making him a false prophet. And if he was a false prophet, then the things he taught are not direction from God on how to return to Him.
If Joseph Smith was a prophet, that also means that every single doctrine he preached as being from God truly was from God. But the reverse is also true; if one single doctrine he taught was not from God, or one translation he made was not inspired though he said it was, the link is broken.
To give a concrete example, the LDS are doctrinally committed to the notion that the languages of the Earth stemmed from a historical event surrounding the tower of Babel, and that the story of the great flood is actual (source). That means that if either of these things did not happen exactly as the Bible would have us believe, then the chain is broken; Joseph Smith was not a prophet, the Book of Mormon was fabricated by men, and the entire truthfulness of the Church collapses.
So one can go in either direction: Joseph Smith must have been a prophet, so everything that is required to make him a prophet must be upheld, or Joseph Smith's deeds appear to be those of either a prophet or a fraud, and the actions are evidence of either one. For example, if polygamy as practiced and preached by Smith was immoral, then the Church is a fraud. One needs no further discussion. If it was immoral but he said it was godly, then he was never called of God, so he must have fabricated the Book of Mormon, constructed his First Vision story, and lied to thousands of people. That means that Thomas Monson is not a prophet either, that the priesthood is man-made and not the power of God, and so on.
This doesn't mean that everything he did had to be a weak link. If what Smith preached about charity is in line with God, then that is a very strong link. He may have dozens of very sturdy, almost unbreakable links in his chain of authority. But all it takes is one single broken link to destroy the chain.
If God did not command Brigham Young and 9 subsequent prophets to refuse temple blessings to persons of African descent, then the entire Church is a fraud because they all said exactly that. If Joseph Smith said he was translating the Kinderhook plates by the power of God, then he was a fraud and/or certifiably delusional.
I think most members don't worry about the chain, though. They focus on the few links they find to be strongest, and ignore what is absolutely necessary to connect them all. Unfortunately, the remaining chain they hold onto may not connect to anything at all if they ever put any weight on it. That's probably why so few members have been willing to honestly address my concerns. If one suspects a defect in a chain, though, shouldn't all his attention go to inspect the faulty link?
ReferenceHinckley, G. B. (2003, May). Loyalty. Ensign, 58-60.