Mousethief mentions the death penalty, and that is rather a good example of what I mean by the conditionality of "rights".

Although I am against the death penalty on principle, there are certain crimes, for example the rape and murder of babies or small children, which are so abhorrent and against all natural laws.... are so utterly beyond redemption, that removing these people permanently from the human race seems the only option.

I would happily put these people out of their misery personally.