The Constitution is a limit on Government, not on citizens. If it's not expressed in the Constitution, then government has no authority to prohibit it, tax it or make laws about it.
It's stunning how many people don't know this, isn't it? Wouldn't it be nice if this were still true?
I thought that if its not in the constitution the FEDERAL government had no authority, but the states' could still pass their own laws prohibiting, taxing and making law...