Yes, I am aware of that argument, but it doesn't conclude anything. The word isn’t in there, but that doesn’t mean the concepts aren’t being followed.
If your assertion is true, than shouldn't "constitutional republic" be in there? Because it isn't. Neither is "federal republic" or "popular sovereignty." Come to think of, use of your Ctrl-F function will also show you that “self-determination”, “state’s rights”, “civil rights”, “civil liberties”, “right to privacy”, "natural rights", “inalienable rights”, or “life, liberty, and the pursuit of happiness" are all notably absent. That doesn’t mean we don’t have them all, or that they didn’t intend them to be followed.
This is my last post on the subject, because if you haven't gotten it by now, I can't help you, but the point is this: a republic is a kind of representative democracy. If you've been through American schools, you should have learned that years ago, because it is Political Science 101.