Yeah, this could, possibly, be a major act of civil disobedience against the Federal Government.
Would Federal tax law apply the same for couples that have a “Marriage Contract” as those who were licensed to marry?
At the least it would create a massive legal and administrative headache that would get dumped into the courts to sort out. If it is different, it means one can be married (with all the contractual benefits of marriage) without the burden of things like the marriage penalty.
If it is legal.
I don't see how all this game playing changes anything, either the relationship will comply with the law for recognition, or it won't.
That was the way it was in 1950, and 1900, and 1990, either you do what the law requires for the government to recognize the union, or you blow off the government part.
Exactly; like would there be any such thing anymore as “married filing jointly”