Are Mormons a "cult"? Based upon the Biblical standard of one true God, they are not a "Christian" denomination as defined by the protestant faith. Their "Jesus" is not Jesus, the Biblical Son of the One True God, but another man altogether. Their religion is based upon the premise that man may become "god", by following the precepts of their faith. They may well follow " a Christ", but he is not The Christ as defined in the Holy Bible.
Mormonism Research Ministry
Stepping back to the central question of whether or not a Bible believer should vote for a Mormon, or for any non-Christian, I think we need to separate our intentions. Are we electing a civil leader or a religious leader? The Constitution is quite clear that our government shall establish no religion" and "no religious test shall ever be required" for public office; I think we need to set the issue aside unless and until we can make a clear determination of "who follows what". At least, in Romney, we know what we're getting, as opposed to so many "Christians on the surface" who vote and represent us in a manner clearly contradictory to the teachings of the Bible.
Amendment 1 - Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
Article Six (part three) - The Senators and Representatives before mentioned, and the Members of the several State Legislatures, and all executive and judicial Officers, both of the United States and of the several States, shall be bound by Oath or Affirmation, to support this Constitution; but no religious Test shall ever be required as a Qualification to any Office or public Trust under the United States.
That being said, I would not cast a ballot for an avowed atheist because this candidate clearly would be an immoral person and that would be reflected in every decision he or she made. "Immoral" in this context is defined by me as subscribing to no definable standard of conduct.
If the choices are a "hypothetical christian" (as in Obama) vs a "cult christian", (as in Romney), I think we have to let the issue of religion drop and look to their platform on the issues alone. Clearly, from the perspective of a protestant Bible believer, neither candidate will reflect the God of Abraham and Isaac, God the Father, "I Am".
"And behold, the LORD stood above it and said, "I am the LORD, the God of your father Abraham and the God of Isaac; the land on which you lie, I will give it to you and to your descendants." ~ Genesis 28:13
"And God said unto Moses, I AM THAT I AM: and he said, Thus shalt thou say unto the children of Israel, I AM hath sent me unto you." Exodus 3:14