Well maybe we should just redefine marriage all together. Why should polygamist be discriminated against.
as Jonathan Turley writes in the USA Today 10/3/2004
Polygamy laws expose our own hypocrisy
....1878 opinion in Reynolds vs. United States, the court refused to recognize polygamy as a legitimate religious practice, dismissing it in racist and anti-Mormon terms as "almost exclusively a feature of the life of Asiatic and African people." In later decisions, the court declared polygamy to be "a blot on our civilization" and compared it to human sacrifice and "a return to barbarism." Most tellingly, the court found that the practice is "contrary to the spirit of Christianity and of the civilization which Christianity has produced in the Western World."
Contrary to the court's statements, the practice of polygamy is actually one of the common threads between Christians, Jews and Muslims.
Deuteronomy contains a rule for the division of property in polygamist marriages. Old Testament figures such as Abraham, David, Jacob and Solomon were all favored by God and were all polygamists. Solomon truly put the "poly" to polygamy with 700 wives and 300 concubines. Mohammed had 10 wives, though the Koran limits multiple wives to four. Martin Luther at one time accepted polygamy as a practical necessity. Polygamy is still present among Jews in Israel, Yemen and the Mediterranean.