The constitution clearly discusses racial equality with Amendment 15.
Only in regards to voting.
The Constitution clearly discusses sex/gender in Amendment 19.
Again, only in terms of voting.
There's a reason why
Brown v. Board of Education utilized the 14th and not the 15th...becuase it had nothing to do with voting. The fact that the 15th was present and pointed out race is irrelevant to the notion that the 14th applies to race. The 15th is singularly about voting rights.
It's not unconstitutional to define marriage as one man one woman.
. . . .sigh
I'm not denying it's currently found to be constitution. I'm asking you WHY you believe that's correct.
What important state interests are there in outlawing polygamy, incest, making bestiality illegal or other such things?
I'm going insane here because it's becoming clear you have no clue what you're talking about and that's why there's a disconnect.
Polygamy can not be argued from the notion of Gender discrimination. If you feel it could be, please present your argument as to how. It can't be argued based on Race either. It would have to be very narrowly tailored to be argued on Religion, and it wouldn't stand up to well since there's no clear discrimination against someone because of their religion. As such,
at best, it'd qualify as needing rational basis scrutiny...the lowest level of scrutiny...and as such doesn't need to have a "Important" state interest but rather a legitimate state interest.
The state has a legitimate interest in maintaining an equitable tax code, as well as being reasonable in terms of public spending in terms of the contract aspects that would need to be dealt with in such situations. Allowing for polygamous marriage creates a plethora of significantly new and unique tax issues due to the potential stringing together of multiple households through contractual marriage and thus creating a swiss cheese setup of tax connections. For example, one man marries two wives. One of those wives marries a second man who he himself has three wives, one of which is also married to the wife that shares both husbands. How is the tax code worked up for those individuals? How would things be settled with regards to divorce, custody rights, power of attorny, etc. Does husband one, husband two, or the wife have precedence.
Beastiality, if you're talking about it in the sense of Marriage since that's the only way that it'd really be relevant to this discussion, has a similar issue with acting that it requires "important" state interest and again is another thing that is questionable as to whether or not it even register for the "rational basis" level of things. But lets assume it does. The state has a legitimate state interest in terms of the legitimacy of contracts and allowing for an entity that does not have the ability to actually consent to be able to enter into a binding legal contract is problematic for that legitimate state interest.
In terms of incestuous marriage, I'm actually one who doesn't believe that should be inherently illegal from a constitutional stand point.
There, for two seperate ones you've provided me I've given you, off the cuff, clear and reasoned examples of a State Interest that the government has in denying them the ability to marry and an indication of how it's needed in relation to the particular discrimination. Something you've yet to provide in this entire conversation in terms of gender.