According to the New Testament, part of a Christian pastor’s job assignment is to warn his congregation concerning false teaching. It is entirely right for him to say that the Jesus of Mormonism is the begotten offspring of an exalted man and one of his many wives who lives on a planet circling a star named Kolob, and his “gospel” is the message of how you, too, can be exalted to godhood. He should point out that the Mormon (LDS) Church denies Christ’s full deity and the “god” they worship is not eternal but merely an exalted man who has achieved godhood by obeying certain laws. He should make it clear that Christianity is actually closer to Islam than Mormonism as both Islam and Christianity affirm monotheism (there is only one God) while Mormonism is one of the most polytheistic religions in existence. It is therefore right for him to say that it is certainly not in any way compatible with biblical Christianity. Where a pastor goes astray is when he then says to his congregation, “you should not vote for any presidential candidate who holds to such beliefs.” Even while he makes people aware of the theological facts, all should be encouraged to vote according to their conscience.
Since writing the above I have come across an interesting article by Dr. Al Mohler on this theme found here, as well as this one by Kevin DeYoung called Mormonism 101.