Sadly for you, Marriage existed Before Christianity was established. That religion has no universal right over the word and the meanings of it.
Of course, I find it weird if they are trying to get a marriage in a Christian way when it's not their religion..
I know that actually (Being chinese, obviously chinese marriage traditions have nothing to do with god or anything)
I was thinking more about US religious marriage though. I guess what Ron Paul meant was to stop producing marriage licenses or give people who have marriage license no special privilages and rights. I think he is over-simplifying the matter because there is the whole deal with inheritence and whatnot and who knows what. It's rather complex issue to make Marriage no different.