ARE MORMONS CHRISTIANS?

The question is a perplexing one: Are Mormons Christians? Most Mormons would probably be offended by the question, because they believe and say that they are. Yet this is a difficult question for others, for a variety of reasons. After all, Mormons accept "scriptures" other than the Bible (e.g. the Book of Mormon), engage in practices unknown in other Christian churches and communities (e.g. secret temple rituals), and believe in doctrines alien to traditional Christian theology (e.g. continuing public revelation).

A FAIR QUESTION

In defense of the question, which offends so many Mormons, Mormons should be reminded that they do not believe that any church is Christian but their own. The very premise of Mormonism is that all other churches are "apostate," otherwise a "restoration" through Joseph Smith would be completely unnecessary. Whether you are Catholic, Protestant, Eastern Orthodox, Oriental Orthodox, etc., Mormons believe you belong to an utterly false and non-Christian church:

Within the first century A.D. ...the Apostles were killed, the doctrines were changed, and the truth was abandoned. A resultant spiritual darkness covered the earth for centuries until one morning in the spring of 1820 when God the Father and his Son, Jesus Christ, appeared to a young boy named Joseph Smith and initiated a restoration of all the truths, powers, and priesthood authority of the ancient Church.
(LDS Global Media Guide: Overview, as it appeared on the official Church of Jesus Christ of Latter-Day Saints website June 2000, emphasis added)

The period of time when the true Church no longer existed on earth [approximately 100 A.D. - 1830 A.D.] is called the Great Apostasy.... There were no Apostles or other priesthood leaders with power from God, and there were no spiritual gifts.... It was the Church of Jesus Christ no longer; it was a church of men.
(Gospel Principles chapter 16: "The Church of Jesus Christ in Former Times," as it appeared on the official Church of Jesus Christ of Latter-Day Saints website June 2000, emphasis added)

A CATHOLIC ANSWER

Who are Christians? The Vatican II document Unitatis Redintegratio clarifies: "All who have been justified by faith in Baptism are incorporated into Christ; they therefore have a right to be called Christians" (3§1; c.f. Catechism of the Catholic Church #818).

What is a valid baptism? Sacramental validity requires proper form, matter, intent, and minister. The proper form for baptism is the Trinitarian formula (Matt. 28:19), i.e. the minister of the sacrament says "(name), I baptize you in the name of the Father, and of the Son, and of the Holy Spirit/Ghost" or "the servant of God, (name), is baptized in the name of the Father, and of the Son, and of the Holy Spirit/Ghost" (c.f. Catechism #1240). The proper matter for baptism is water. The recipient may be completely immersed, partially dunked, or have the water poured over him by the minister (c.f. Catechism #1239) while the proper formula is spoken. The minister's intention must be to do what the Church does, i.e. to baptize (c.f. Catechism #1256). Orthodox belief about the sacrament and faith in its efficacy are not required for the intention to be valid (c.f. 1993 Directory on Ecumenism 95b). The ordinary minister for baptism is a priest or deacon, but baptism may be validly administered by any person, even a non-Christian (c.f. Catechism #1256). "Any person" does not include the recipient. A person cannot baptize himself. (The recipient of baptism, just for the record, may be any living person who is not already baptized. c.f. Catechism #1247.)

Do Mormons use proper form, matter, intent, and minister? According to a 17 July 2001 Catholic World News article:

The baptism conferred by the Mormon sect is not valid in the eyes of the Catholic Church. That announcement-- which represents a change from past assumptions-- came from the Congregation for the Doctrine of the Faith.

In the July 17 issue of L'Osservatore Romano, a Jesuit theologian-- Father Luis Ladaria-- explains the decision from the Congregation. The decision came in the form of a negative answer to a question, or "dubium," about Mormon baptism. As Father Ladaria points out, it is "a change from the past practice" of accepting the validity of the Mormon rite. [The change in practice comes because the previous presumption in favor of validity was not yet fully informed.]

Church doctrine on the sacrament of Baptism, tracing back to St. Augustine, ordinarily makes it clear that the validity of the sacrament does not depend on the sanctity of the minister. The Council of Trent taught that even heretics could confer valid Baptism, provided that they baptized "in the name of the Father, and the Son, and the Holy Spirit," and intended to baptize the individual into the Christian faith. The current Code of Canon Law stipulates that an individual baptized in any Christian community should not be "re- baptized" upon entering the Catholic Church.

However, the Congregation for the Doctrine of the Faith determined that the faith of Mormons is sufficiently different from Christian doctrine so that the baptism conferred by that sect has a different significance. The Congregation notes that the Mormons believe that "God the father had a wife, the Celestial Mother, with whom he procreated Jesus Christ and the Holy Spirit." The Vatican concluded, therefore, that "this is not the Baptism that Christ instituted."

See the full text of the Catholic World News' report.
See the full text of the Congregation for the Doctrine of the Faith's official answer.
See the full text of Fr. Luis Ladaria's explanation. See more commentary by Fr. Urbano Navarrete.