I am somewhat confused by your response.
For example, I agree with you that putting information about who inherits my house in my will is the obvious thing to do. But what I'm asking is, if I die without having specified who inherits my house, is determining who inherits my house a government issue, or not?
If it helps, in most jurisdictions the U.S. today, the mechanism for this determination is controlled by law, which is understood to be a function of the government. I don't know whether that's sufficient to make it a government issue, or not.
If it is a government issue, then marriage in the U.S. is a government issue as well, since one of the things the government must establish in order to make that determination is whether I am married and if so to whom.
It is a government issue, and it is a good point. I don't think (but I'm not sure) that it's not good enough on its own.
At the very least, the government should stay out of marriage when possible, and they should keep everything optional (perhaps you don't want your spouse to inherit your stuff).
If it is a government issue, then marriage in the U.S. is a government issue as well...
It's fuzzy. That means that it's at least a little a government issue, but not necessarily important enough that they really should do it. You could find some reason why the government should care about anything.
A thought occurred to me today as I skimmed an article in a rationality forum where the subject of gay marriage cropped up; seeing as the issue has been hotly contested in various public fora and especially the courts, what about poly? After all, many if not all the arguments for gay marriage apply to poly marriage as well.
Questions for LWers who are currently in a such a relationship, or have an opinion to share:
Do polies want to marry each other or do such relationships not lend themselves to permanence above a threshold of partners? Should polies campaign for the right for a civil union anyway? what are the up and down sides of this? etc