They would only have equal rights if this civil union equivalent was pretty much a copy of marriage law. The same is not true for for "incestuous couples" as they are already have many of those rights. Don't obfuscate the point of my argument: one group needs marriage or a marriage equivalent, the other group does not.
It certainly is not my intent to obfuscate. In fact, I think I agree with you.
Let's consider couple A and couple B. Both desire the rights associated with marriage. (They might desire those rights for themselves, or they might desire those rights on behalf of minor children they are raising.) Couple A has none of those rights. To get them, they get married. Couple B, however, already has some of those rights, so the state invents a new entity called marriag. It grants people all of the rights of marriage, except those already enjoyed by couple B. The state refuses to let couple be participate in marriage, but allows marriag. Now, couple A and couple B have equal rights. Couple B did not need marriage or a marriage equivalent, because they could get those rights via marriag.
I agree. Couple B does not need marriage.
However, many would object. Although, technically, the two couple have equal rights, the very fact that one of them is called "marriage" and the other is called "marriag". is, all by itself, enough difference to say that the two couples do not, in fact, have equal rights. In order to get the rights of marriage, according to this argument, they must have marriage itself.
In other words, according to many, there is no such thing as a "marriage equivalent". They would say that gay and straight people in the United Kingdom do not have equal rights, because in the UK, opposite sex couples can get married, while same sex couples can get a "civil partnership". This, according to those who advance this argument, would be constitutionally unacceptable in the United States, because it does not grant the couples exactly the same rights. They are identical, except in name, but that would not be considered satisfactory to many.
By calling it "less than marriage" you show your own bias:
It isn't me that calls it "less than marriage". It's them. They say that those in the UK with "civil partnerships" have something less than marriage. My personal opinion is that UK civil partners have the equivalent of marriage.
No, I don't understand. Which "laws about sex" are closely intertwined with marriage?
(I fancy Skeptic is shaking his head as I try to answer this, but here goes.)
Of course, historically, the two were totally intertwined. For example, in many places, it was a crime to have sex with anyone other than your lawful spouse. No exceptions. In some parts of the world, of course, that is still the case.
Here in the United States there are still examples of laws where sex and marriage are related. Although adultery is no longer a criminal offense, it can still be presented as evidence in divorce proceedings. Some states also recognize "at fault" divorce, and impotence, adultery, or various euphemisms for "not putting out" are all recognized as grounds for divorce. A recent court case affirmed the right of a police department to sanction one of its officers for adultery. (I didn't save the link, but I found it while looking up information about incest.)
In many states, it is illegal for people below a certain age to engage in sexual intercourse. This is the case regardless of consent, and regardless of the relative age of the partners. Sex below a certain age is a crime. (ETA: Technically, I think the actual crime is sex with a partner who is below a certain age, regardless of your own age.) However, there is an exception for married couples. Young people in some of those states are allowed to get married (sometimes the permission of a judge or the parents is required). If they are married, their sexual relations are no longer a crime.
