One of the hottest topics in the last 10 years is that of so-called gay-marriage. Everybody knows you have to go to the local county government to get a valid marriage license, but why?
The history of marriage is about property. Marriage was a way that kingdoms could unite, wealth could be shared and the offspring of men could be counted. Marriage today is less about uniting kingdoms or fortunes, and more about love and attraction, nevertheless, when that attraction dies, or the faithfulness to the institution deteriorates, it is the job of the state to split up the combined fortune of a couple in the divorce proceedings.
Churches claim marriage as their own, but that harkens back to the middle ages when the power of the state was granted by the priesthood of the church. Today churches do little with marriage beyond performing a ceremony.
So what happens when a marriage dissolves? Does the church get involved helping to split up the wealth? No, that is left to civil governments, which is why civil governments have to authorize the marriage contract. For the law the dissolve a contract, it must recognize the contract existed in the first place, thus, government has to be involved in marriage, if only so it can adjudicate divorces.