I also happen to agree with Ron's construction that rights are "inalienable" but may be restricted by the action of authority.
The question remains: What exactly is the nature of a "right"?
My thinking at this moment is that "rights" are a logical political/social construct which attempts to define the maximum range of action an individual may have without trespassing on another's similar claim.
The obvious reason for such a thought process would be to set logical guidelines within which an otherwise non-hierarchical group of humans could exist and avoid conflict. As such, the concept of rights seems to me to be a practical concept aimed at conflict reduction.
The issue of pre-existence seems IMO as seems only an extension of human nature in this specific situation. That is to say, humans cannot conceive that which is beyond our conception. And so it is difficult to conceive of a world without us and out conceptions.
And in a similar fashion, our consciousness logically concludes that anything that exists which we did not create was therefore pre-existent. And since no human created "rights", it seems obvious that they must be pre-existent. But this pre-existence seems to me no different in character than the "pre-existence" of the number two, or 90 degree angles.
Absent human consciousness, "rights" cease to meaningfully exist. Absent a social milieu, "rights" cease to meaningfully exist. In such circumstance, I cannot imagine how it is that rights can be said to "pre-exist."
Inalienability is, IMO, a characteristic that one may choose to attach to rights at their definitional inception.
I propose the following as an exploratory example case. Let us suppose that we grant the justice system authority to impose a variety of punishments. And, let us suppose that capital punishment has been outlawed. And so some future president bush comes up with a novel new punishment to evade this restriction as possible. This new punishment would consist of a treatment that would permanently remove all consciousness. The criminal's body would remain alive, but permanently comatose and brain dead. How is it meaningful to discuss the "rights" that are retained by this alive individual? He/she may retain his rights in theory, but the restrictions on exercising those rights are total and comprehensive. And so the his/her retention of rights is in this case nothing beyond a theory. And so, in this case, when one says that each alive individual retains his full rights, we are simply exploring our defined conception of rights and not the characteristics of some pre-existent reality . And in that sense, inalienable rights are simply a logical and definitional artifact of our philosophical discussion of the nature of rights ... which in turn is nothing but a concept that we have created.
So when people say that rights are pre-existent and inalienable, I hear them saying "I define rights as pre-existent and inalienable. And we can see this is true because when we examine these rights... we find that they are pre-existent and inalienable."
