I just came across this wonderful article in Time archive: link

"Morality: The case for Polygamy" about an article by Massachusetts-born Father Eugene Hillman a missionary for 16 years in Tanzania.

Polygamy only hope of marriage for many women
Changing polygamous practices to monogamy in cultures is not the mandate of missionaries with regards to social structures that are not evil
Polygamy common among ancient Jews, laws of Moses
OT word for wife "is used regularly with reference to marriage cases which may be either polygamous or monogamous"
One flesh - "the several children of one mother may be regarded as 'one flesh' with her by reason of their unity in generation and maternal love"
Makes reference to "socially valid polygamous marriage" which lets a man be "conjugally united with each of his wives repsectively, since each does become with him 'one flesh'"
Just bring the whole polygamous family into the church

Searches

google: Father Eugene Hillman polygamy
- Hypocrasy of Monogamy - polygamy vs. serial monogamy and divorce

Article - Morality the case for polygamy