the Constitution says no one has to testify against themselves
that is a right
But why does it say that? The right not to testify against yourself is not like the right of free speach or religion. Rather, it is like the right not to have soldiers stationed in your house. It exists to prevent an abusive practice that was common in that era.
only changing the Bill of Rights cahnges that
not some device
Obviously, removing the 5th admendment would require changing the Constitution. However, there does come a time when doing so is a good idea. And a sufficently accurate lie detector would be such a reason.
Jay