[NutCrackerBoy]

By definition, marriage is a union between a man and a woman.

I agree. Then the other side says "words are malleable." What then?

[PeoplesRepublicOfWashington]

Words mean things, especially in law. If a word is as malleable as your opponents claim, hammer it back to its definition. If they persist, find an absurd change of definition to inflict upon them.