This comment was from NickMostly in reply to AnonymousDog on the post Are Marriage Rights Civil Rights?
Don’t forget that there must be at minimum a rational basis for any law that discriminates against a class. In general a person who has reached majority age is not prohibited from associating and entering into a contract with another individual and the 5th and 14th amendments protect individuals from being discriminated against by the law – both state and federal.
There is no rational basis test that can not apply equally to heterosexual couples as it does to homosexual couples. The only purpose the state has in restricting marriage — and the rights and protections it bestows — to heterosexuals is to preserve “traditional marriage.” Of course, there is no such thing, as marriage has been redefined by each successive generation.
The discrimination you fail to see is that the marriage contract is restricted by sex without any rational basis for doing so. Sex is not the same as number; there is a difference between saying “any two people of majority age may enter into this contract” and “any two differently sexed people of majority age may enter into this contract.” I believe this latter restriction is similar in tone and tenor to “any two people of majority age and the same race may enter into this contract.
So the challenge for opponents of marriage between two people of the same sex is to come up with reason that will withstand a rational basis test that won’t also disqualify some heterosexual couples from being married. I don’t believe a defensible purpose exists.