No, at the very point that Caesar claims for himself the definition of marriage, he has usurped that which is not his.
Biblically, Caesar's only scripturally-legitimate office in regard to Marriage is to punish breach of Contract, such as Adultery -- the definition of the Marriage Contract itself is (on every single page of the Bible) a matter of Private and Religious authority, NEVER THE STATE.
Rendering unto Caesar that which is not his (the definition and establishment of Marriage) is a Sin.
By the way, I saw your other post about ancient Israel. Remind me how adultery was dealt with in those times?
Adultery -- the BREACH of Contract -- was punished by the State.
The Contract itself was established by Private and Religious vows, not the License of the State. The State's responsibility was only and exclusively to punish the BREACH of Contract, according to the terms that the Contractors themselves established.
See Deuteronomy chapter 27, verses 14 through 26 -- the Ratification of the Law was a matter of voluntary mutual covenant, not State Mandate. If you care to admit that voluntary mutual covenant (not State Mandate) is the Biblical Standard for the ratification of the Law of God (as recorded in Deuteronomy chapter 27)... then I rest my case, having won the entire argument.
If Privatized Marriage was good enough for the Patriarchs of the Faith, it's good enough for us.
If voluntary mutual covenant (not State Mandate) is the Biblical Standard for Ancient Israel, then the same is true today.
Hmm. 100% congruent principles of Law. Interesting, that.
Best, OP
Was this a civil or criminal punishment? If the latter, then it would be difficult to term it a mere contractual matter. Besides, try "going in unto" someone you weren't "contracted" to at all, and see what would have happened then.