Did Joseph Smith send men away on missions to secretly marry their wives while they were gone?

There is no evidence to suggest that Joseph Smith sent men on missions so he could marry their wives. To answer this charge, the first question that has to be answered is, for Joseph Smith how many wives were already married? Smith was sealed to about 30-40 women, about 10 of whom were already married. 

The second thing to understand is that the origin of the argument that Smith married missionaries’ wives comes from an affidavit by John C. Bennett, an opponent of the Mormon Church. Bennett said that Smith sent men on missions so he could marry their wives. The first problem with this argument is that it came from a notoriously antagonistic source: John C. Bennett. Bennett also knew about plural marriage and used it as a cover to have sexual relationships with women that he never married.

Another problem with this argument is that historians have found that only one of Smith’s confirmed plural wives had a husband who served a mission. This was Marinda Nancy Johnson, whose husband was Orson Hyde. There is another issue with this argument. There are two dates for Smith’s sealing to Johnson. One of the dates was a year after Hyde left on his mission and the second date was after Hyde got home from his mission. Either date does not provide a strong argument that Joseph Smith’s polygamy was deliberately sending men on missions to marry their wives, nor does the fact that this is the only confirmed case of Smith marrying a woman whose husband was on a mission. 

The only other possible plural wife whose husband served a mission is Lucinda Pendleton Morgan whose husband was George Harris. Harris was called to serve a mission in July of 1840 and served for fourteen months. Morgan might have been sealed to Smith, but the date of the sealing is unknown.