Quite obviously the state has the legal authority. That can be understood by anyone with the smarts of a doorknob. The question, is whether or not the state SHOULD have the legal authority (i.e., does the state have the moral authority)
The Third Reich granted itself the legal authority to roast Jews to death. It did so however, without the moral authority.
See the distinction?
#2. The state IS a party to the marriage contract.
My marriage was a convenant between myself and my wife. I did not marry the state. Perhaps you did... but I did not.