I don't think you really get this American Constitution thing. Read up on "negative rights" and get back to me. I prefer you having absolutely zero say in what my rights are, and that goes for the rest of your collective, too. In America, the Constitution restricts the government, not the other way around. It's not an easy concept for Leftists, but you can get it if you try.
So from that I take it you look to the Constitution. Positive or negative, there's a process laid out there to determine if rights, pre-existing or not, are being abridged as well as a process to determine remedies.
As you point, out it's possible to codify negative rights.