I don't understand what you're trying to say. What does the death being either right or wrong mean?
Probably a fair question. But i don't understand it. Can you rephrase?
You said the death penalty isn't always wrong. What does that mean?
The death penalty is not something that can be sometimes right or wrong. It's always right, unless later proven to be wrong.
As taks mentioned, there's always a chance that someone innocent, or at least, not guilty enough, will get executed with most systems. So in my mind either you see the death of these people as being acceptable losses, thus the death penalty is "right", or you see their deaths as unacceptable, thus the death penalty is "wrong".