On a serious note, I believe that:
1. Canada should prohibited the contracting of a polygamous marriage in Canada (due to the harms inherent in polygamous marriage),
2. Canada should recognise a polygamous marriage that is legally contracted abroad (since breaking up an already-established family is harmful in its own right, even it could unfortunately allow for a legal loophole: as harmful as polygamy is, breaking one up after it is already done simply compounds the garm), and
3. Given the precedent with gay marriage, it will probably face a charter challenge and eventually become legal no matter what I think.