Government might soon. And many here are arguing that the government gets to define marriage. I wonder what they will do when the government says same sex couples are married? Or when it says you can marry your pet?
Setting up government as the arbitor cuts both ways.
As far as government benefits are concerned, government gets to decide. But REAL marriage is not decided by government, just their rules in passing out favors.
Govm't has no right to define what is marriage whatsoever. The must recognize what the culture determines marriage is. Regardless of the various particulars found about why it is so, marriage is universally a contract between a man and a woman. That is what govm't must accept. If they don't, then any govm't action contrary to that is illegitimate. Govm't is also not an arbitor hear, nor does it have the right to do so. It must simply render itself an observer and report what it finds. ie. marriage is a contract between a man and a woman.