To either support his own guilt feelings or to accommodate the gay marriage lobby or because of pressure from his son and/or his wife Republican Congressman Rob Portman has turned the meaning of marriage and libertarianism on its head. See the following confused explanation of his new stance:
Proud’ Dad Portman Flips to Support Gay Son on Same-Sex Marriage.
I cannot claim to know what is going on in Portman's head; but, I can evaluate what he says publicly and the policy stand he takes. The libertarian position can only be defined as one where the state has nothing to do with marriage. It would be fine and justifiable if he had taken that position and said that he had "re-thought" the question now that his son is at Yale and gay that state policy should say nothing about marriage. Here he would be saying that government should get out of any recognition of, or any involvement with, marriage. That would not be a stand for "gay marriage" or any definition of marriage. It would be saying that people should be allowed to live as they want and with whom they want to and it is not the state's business.
But, Portman does make it the state's business.
If the state is going to recognize marriage, from a conservative point of view (and a libertarian one), it can only be because the state recognizes some overwhelming state, or societal interest. These interests must at least be in the area of survival and/or national, i.e. state, security. Nothing here would lead someone, under any circumstance, to support "gay marriage." And neither can Representative Portman.
The state has for a long time recognized marriage as exclusively between one man and one women because of long standing historical and religious reasons. Today under this theory it would be legitimate to exclude "gay marriage" under conservative concepts; but not under libertarian ones. Libertarian concepts would at best say that there is no place for the state to be in the marriage definition business. There are many, many definitions of marriage. Why would one or two take precedence over all the rest?
This is Portman's betrayal and the lie presented by his son. It is also the lie which most gay activist present.
The only, and I mean only, reason that the state can justify in having an interest in marriage is national suicide as it relates to national security. There is nothing in being a conservative or a libertarian that requires an individual or a society to commit suicide. Therefore the one and sole state interest in marriage is the consequence of that coupling, which is more children. Only the increase in fertility, i.e. new babies, justifies and explains the state's interest in marriage. Under these principles, there would be greater justification for polygamy than there is from gay marriage. (All states have a greater justification for polygamy than gay marriage; although, there are other social problems with polygamy.)
All these couplings have minimal advantage or no advantage to fertility: gay marriage, bestiality, general fetishes, co-habitation, marriage to inanimate objects, etc. As a consequence, the state cannot and should not have anything to say, as far as policy, about these.
Portman, understandably as a bereaved father, has turned state policy on its head when it comes to gay marriage. He not only betrayed his principles; he also stood the conservative and libertarian cause on its head. There is no reason for him to continue in politics representing conservative/libertarian ideas.