It is true that at one time Mormons practiced Polygamy, but it is often overplayed, misunderstood and sensationalized by detractors. The facts are that during a period of early Church history, the law of plural marriage was practiced by a small portion of church members. Before anyone overreacts to that admission it would be well to remember two points:
(1) Plural marriage has been practiced throughout the ages for short periods of time when directed by the Lord for his purposes, as in the cases of Abraham, Isaac, Jacob, and others.
(2) Joseph Smith Jr. by his sacred calling, held the keys and the authority, as a part of the promised restoration of all things, to excercise this principle when so directed by the Lord. Joseph Smith said, “I hold the keys of this power in the last days; for there is never but one on earth at a time on whom the power and its keys are conferred; and I have constantly said no man shall have but one wife at a time, unless the Lord directs otherwise.”
So, why did some early Mormons practice plural marriage? Simply because they were commanded to do so by God through His prophet.
In Mormon doctrine, plural marriage is not an essential principle of the gospel, nor is it preferable to monogamy. The Lord, however, may choose to command, forbid, or tolerate this practice among his people as he deems it necessary or appropriate. Indeed, he has done all three!
Far from being a whoredom or a sordid practice, polygamy was governed by strict limits, order, and mutualy agreement when entering ito and, if necessary, terminating the practice. Those who entered into polygamy were pure in heart and strictly virtuous. Those who perverted or abused the system recieved imediate and heavy condemnation.
Concerning Western culture’s general abhorrence to plural marriage, Professor Stephen E. Robinson of Brigham Young University wrote:
The roots of this abhorrence can hardly be described as biblical, for the Old Testament explicitly sanctions polygamy, and the New Testament does not forbid it. The practice could not have been abhorrent to Jesus and the first-century Jewish Christians, for their culture was not Western and plural marriage was sanctioned in the law of Moses, the holiness of which was endorsed by both Jesus and Paul.
Even the early Christians saw that polygamy was a custom not out of harmony with the church. Saint Augustine, the great philosopher and Catholic convert who became the Bishop of Hippo, responded to the church’s condemnation of polygamy: “Jacob the son of Isaac is charged with having committed a great crime because he had four wives. But here there is no ground for criminal accusation: for a plurality of wives was no crime when it was the custom; it is a crime now because it is no longer the custom…the only reason of its being a crime now to do this, is because custom and the laws forbid it.” The same was true of the early LDS Church. In 1890 President Wilford Woodruff, then the prophet of the Church, issued the Manifesto, as directed by the Lord, commanding the practice of plural marriage to cease because antipolygamy legislation threatened to confiscate Church property, including Holy Temples. Today , because God forbids the practice, all who engage in plural marriage are guilty of great wickedness and are subject to excommunication from the Church.

BJ