Marriage should have never become part of the issue. The major mistake was when certain Conservatives wanted to refuse same sex couples from receiving the same treatment on taxes, etc. as traditionally married couples. Had the Republicans at that time said, "Sure, they should be treated equally in that regard", we would have taken the primary issue of mistreatment away from the gay community.
Marriage is between a man and a woman and there is no reason government shouldn't sanction it as that. It is in the best interest of the nation overall to do so. So give same sex couples the same "rights" to civil unions and the benefits of being united by civil union, but protect marriage for what it has been both traditionally and religiously.