Would it count as evidence against this thesis if the LDS church rejected polygamy even in nations where the practice is legal?
The initial challenge is explaining the change in LDS position in 1890, and I think there's not doubt that it was sparked by the persecution it was receiving from the US. I presume that in the intervening 110 years, the ban on polygamy has taken on a considerably stronger valence, so I don't see that LDS practices in those countries where polygamy is legal (primarily Moslem countries where, I suspect, the LDS missionaries are most unwelcome in any event) would count as evidence for what triggered the initial event in the US in 1890, when the Church was restricted, I presume, almost entirely to the US.
sandy