A blogging conversation has been taking place on the perennial question of the Christianity (or lack thereof) of Mormonism. Participants have included:
- Ben Witherington III, an evangelical New Testament scholar. [8-27-2012]
- Kevin Barney, an LDS attorney and Mormon studies scholar who blogs at By Common Consent. [8-27-2012]
- William J. Hamblin, an LDS professor of ancient and medieval Near Eastern history at BYU. [8-28-2012]
- Rob Bowman, Jr., an evangelical Christian apologist and the Director of the Institute for Religious Research. [8-29-2012]
I feel that Latter-day Saints and evangelical Christians often talk past one another on this matter out of a failure to understand what is even being asked by the question, “Is Mormonism Christianity?” or its related counterpart, “Are Mormons Christians?” I propose that people may ask, understand, and engage these questions in three distinctive senses, and that much of the confusion results from conflating one sense of the question with another. What follows is my own parsing of the ways in which people may interact with this issue. 
1. The Religious Taxonomy Question
How do we classify Mormonism from a strict religious studies perspective? If Christianity is represented by a family tree (for example, the diagram below from my own denomination‘s Web site):
Does Mormonism belong somewhere on that tree? Or should it be represented as a smaller tree springing up next to the bigger tree? Judaism is represented on the tree as providing a base for the rest of Christianity, so it would seem that, even if one feels that Mormonism has grown into something that could properly be defined as its own religion, its Christian roots and heritage should be acknowledged.
Those who interact with the question in this first sense care not whether Mormonism belongs to what evangelicals might call “orthodox Christianity”—or rather, they only care about it in as much as that gives them useful information on how rival religious groups perceive themselves and others. A person looking to answer the question in this sense would likely not disqualify Mormonism for, for example, rejecting the Nicene Creed, because 4th and 5th-century followers of Arianism also rejected the Nicene Creed, yet they should undeniably be categorized as part of the Christian tradition.
Confusion abounds because, when evangelical Christians accuse Mormons of being “not Christians” in the second or third sense (see below), Mormons often respond by defending their Christianity in the first sense, as does Kevin Barney in his post at BCC:
The fact is, [Latter-day Saints] are Christians in the generic sense of the word, even if, from an Evangelical point of view, they are theologically in error and unsaved (i.e., being a Christian is not necessarily tantamount to being right). I personally would have no difficulty with certain shorthand distinctions that would make clear that Mormons neither are nor claim to be creedal or orthodox Christians. But to say they are not Christians at all without such a modifier is to fundamentally misrepresent the nature of their beliefs.
My own answer to the question in this sense is ambivalent. I think one can make a solid case that Mormonism should be categorized as a branch of Christianity. I also think one can make a solid case that it is different enough to warrant classification as a new religious tradition altogether, so I would disagree with the certainty expressed by Barney.
2. The Orthodoxy/Heterodoxy/Heresy Question
When evangelicals assert or argue that Mormonism is not Christianity, often what we mean is that Mormonism is not sufficiently close enough to what we regard as Christian orthodoxy to warrant recommendation or endorsement, hence we launch into lists (similar to the one presented by Witherington) of reasons why Mormonism does not qualify for “Christianity.” What we are really saying with such lists is that Mormonism is a heresy (or the equivalent thereof) and we wish to distance ourselves from it and discourage others from believing in it. Again, confusion arises because often those of us who deny the Christianity of Mormonism in this sense wish to deny its taxonomical classification as well. We often do ourselves and others a disservice here because, as Barney correctly observes, non-evangelicals who ask this question are probably looking to have it answered in the first sense, not the second.
Nevertheless, what evangelicals are doing in this regard is really no different from what Latter-day Saints have recently taken to doing in addressing the matter of their own splinter groups and movements when it comes to the term “Mormon.” For example, the Church-owned site MormonsAndPolygamy.org boldly declares, “There are 13 million Mormons in the United States and around the world, and not one of them is a polygamist.”  Other news releases and statements from Mormon leaders have asserted that, “There is no such thing as a ‘fundamentalist’ Mormon,”  eliciting protest from polygamous members of splinter groups who say that they are, indeed, “fundamentalist Mormons.”  What Mormons really mean is that these groups do not qualify for Mormon orthodoxy or true Mormonism and, therefore, they wish to distance themselves from their teachings and practices. Yet, from a strict question of religious taxonomy, Mormon splinter groups are undeniably “Mormon” in the sense of having descended from the followers of Joseph Smith who were first called “Mormons.” Unlike the question of “Is Mormonism Christianity?,” there is not even a tepid case to be made for classifying Mormon splinter groups as anything other than “Mormon.”
Finally, while this practice has largely fallen out of vogue, I do wish to point out that, historically, Mormons have sometimes denied that other Christian groups qualify as “Christians” or “true Christians,” and that vestiges of this practice still remain in official Mormon materials. For example, I am certain that many members of Orthodox, Catholic, and Protestant Christian faiths would be surprised to crack open the current Gospel Principles manual and learn that Emperor Theodosius I (who is revered by many members of these traditions) was among “those called Christians” and that he “adopted . . . false Christianity as the state religion.” 
My own answer to the question in this sense is that I view all of the world’s religions and religious ideas as occupying a spectrum from “most correct” to “least correct.” Religions fall into different areas of this spectrum which might broadly be labeled “Orthodoxy,” “Heterodoxy,” “Heresy,” “Non-Christian,” etc. I place Mormonism far enough out on the spectrum that it would qualify for or rival the category of “heresy.” Though it is a religion that I deeply respect and admire, it is not a religion that I would personally recommend to a friend who is searching for a church home. To some extent, I must disagree with Witherington and many other Christian writers then, because I feel it is more accurate and less confusing to say that Mormonism is or rivals Christian heresy than to say that it is “not Christian.”
3. The Soteriology/Discipleship Question
The final sense of this question involves use of the word “Christian” as a personal expression of belief in the salvation of another or acknowledgement that a person is sincerely emulating the teachings of Jesus Christ. Evangelicals believe that the “body of Christ” is an entity that transcends denominational boundaries, and most of us would say that a person can believe in at least some errant or false teachings and still be saved. For example, hierarchist evangelicals and egalitarian evangelicals  usually acknowledge that members of the other group may be saved, Arminians and Calvinists usually acknowledge that members of the other group may be saved, and so on. Conversely, it is possible for a person who perfectly affirms evangelical Christian orthodoxy to be a “not Christian” in this sense. The question is, can a practicing member of the LDS church be a “Christian” in the sense of being a member of the body of Christ and a true follower of Jesus Christ? If a member of the LDS church truly comes to believe in Christ, must such a person inevitably come out of the church in order to evidence his or her salvation?
One need not believe in the existence of a spiritual entity known as “the body of Christ” to make proclamations on the Christianity of someone in this sense. For example, I have sometimes seen atheists or agnostics get angry at Christian participants in debates and declare that they are “not Christian.” This is almost never because the non-Christian thinks that the Christian has violated Christian orthodoxy in some sense, but rather, because the non-Christian thinks the Christian’s behavior is not a good emulation of the teachings of Jesus Christ. This functions as the secular equivalent of this sense of the question.
Witherington affirms that there are Christians within Mormonism, though he regards them as necessarily ignorant of church history and New Testament teaching. Many Christians who assert or argue that Mormons are “not Christians” are largely concerned about the second sense of the question, but they often have the third sense in mind as well. There is no parallel for this in the main branch of Mormonism, because lack of membership in The Church of Jesus Christ of Latter-day Saints automatically confers salvific penalties which must be remedied, posthumously if necessary.
My own answer to this sense of the question is that I am a soteriological inclusivist, as are/were theologians such as Gregory Boyd, C. S. Lewis, and Thomas Aquinas. I think that people may be saved in spite of believing in false religions. It is not a common position in evangelical Christianity, but it is not without historical Christian precedent. So I do affirm that Mormons may be Christians in this sense, even without ever leaving the LDS church or internally abandoning its distinctive teachings.
I hope that an understanding of the different senses in which people intend and respond to this question sheds a small amount of light on a subject that usually generates little besides heat.
 I vaguely recall, maybe a year or so ago, reading a post from Rob Bowman that was posted at the atrociously-moderated Mormon Dialogue & Discussion forum which also argued for three senses of understanding this question. I have been unable to locate this post. I am not certain how similar my own post is to Bowman’s. If anyone finds it, please notify me and I’ll be happy to give credit to it in this post.
 http://www.mormonnewsroom.org/commentary/fundamentalist-mormons; see also Gordon B. Hinckley, “There is no such thing as a ‘Mormon Fundamentalist.’ It is a contradiction to use the two words together,” October 1998, http://www.lds.org/general-conference/1998/10/what-are-people-asking-about-us?lang=eng. Pro-Mormon, unofficial apologetic groups such as Mormon Voices have followed the church’s cue in denying the term “Mormon” to rival followers of Joseph Smith: http://mormonvoices.org/103/polygamy.
 Principle Voices, “PRESS RELEASE: ‘Fundamentalist Mormon’ is the Correct Term Contrary to LDS Church Claims;” Web site currently unavailable, see Google Cache here.
 Hierarchists usually self-identify as “complementarians;” that is, evangelical Christians who deny that women may be ordained as pastors and affirm that Christian husbands are to exercise headship in their homes, similar to the Mormon position. Egalitarians promote the ordination of women and affirm that men and women are equal in authority in both the home and the church.