In fact, that is why Mitt’s family moved to Mexico over a century ago so they could continue that old tradition.
Nathan is correct in a way. The LDS actually practiced polygamy secretly until the 1920’s (long after the first ‘manifesto’ and until the second one) and many did move to mexico, including Mitt’s family.
However, they still BELIEVE in polygamy, just only have one wife at a time. Mormon marriages are considered to be ‘for eternity’ so a man (not woman) can marry in the temple (for eternity), divorce, marry again in the temple (without first wife’s permission) for eternity and upon her death, marry again in the temple (for eternity) and have 3 wives in heaven.
Also, there is a belief that polygamy will be re-instituted in this life during the end times, which also has a Mormon POTUS, and is why some LDS I know support gay marriage because they see the next step is the legalization of polygamy.