to expand on that, the govt can not only discriminate, it can limit people's rights. However, in order to do so, it must show that the govt has a legitimate interest in doing so and that the discrimination (or limiting of rights) serves that interest
I can't think of a legitimate governmental interest that is served by limiting marriage to opposite sex couples.
I can't think of one that I've ever heard an argument that convinced me it could arguably be
substantially related to serving an
important state interest...as would be the case with gender.
However...
Even though I may not fully agree with them, I at least think there are some reasonable arguments that I've seen in suggesting that its
rationally related to serving a
legitimate interest.
While I may not always share a persons views or stances, it is possible to objectively put myeslf into the shoes of someone else and attempt to view a situation honestly from a different position than mine.
Given the pyramid scheme system we have implace in this country in terms of welfare benefits, specifically speaking of social security, I think a legitimately plausible argument could be made that "adding to the amount of children born in this country" is a "legitimate" interest of the state. New tax payers are absolutely necessary to continue the current system. I aslo think it could reasonably be argued that providing marriage benefits is rationally related to that since married couples are more likely to have children, and because a same-sex couple is significantly less likely to CREATE a child (as opposed to adopt) due to the simple realities (either logistically, or financially) in doing it there is not a similar rational relationship between providing them marriage benefits.
Ultimately, I think there are some flaws and issues in the argument based on my personal opinions and views, but I also recognize my opinions are views are not objective truth and fact. Stepping outside of my own biases, I can see the argument as one worthy of actual thought and consideration.
An example that actually IS going into my own biases and thoughts is the notion of upholding tradition. I think one can actually argue a legitimate state interest, but absolutely not an "important" one, in upholding and maintaining a foundational "tradition" regarding various things within the country. I believe it's beneficial to a nation for the majority of it's citizenry to have various ideals and traditions that are widely held that help to establish a baseline "oneness" that enhances the tribalism of said citizens which is an absolute benefit to the state. And I do see how disallowing the change of same sex marriage, when being viewed rom a lower teir standard, could be rationally related to serve that. However, what muddies it is that sexual orientation is technically a lower teir classification, but judicial precedence suggests that a bit of extra weight can be required on the part of the state interest in cases involving it...not to the level of needing to be an "important" interest, but needing to be slightly more than simply "legitimate". I personally don't know if I believe that this interest reaches that level, but I do think it's inaccurate to act like the state does not have a legitimate interest at all in facilitating a tribalisic/patriotic mentality within it's populatoin through the maintenance of "traditions".
That's two off the top of my head. I can think of some definitely reasonable arguments regarding legitimate state interest and/or how disallowing same sex marriage rationally relates to it. I generally don't agree with most of them, but I don't think they're generally wholely unreasonable to make.