anon, Your original point was on their antagonism towards polygamy. Then you brought up their moral views. My point was that Americans antagonism towards things are not the same as what they believe moral.
In any event, larger shifts in public opinion have occurred rather quickly, whether it was interracial relations (once also considered immoral and great antagonism towards) or a whole host of other issues. My point being, polygamy is achievable from a legal standpoint and an act of the Legislature.