It is not a deterrent. Instead it is revenge. If convictions were 100% accurate, it might be debatable. If any man is wrongly executed, that is wore than two guilty men being set free.
If, when defending your support for Donald Trump, and your response is,
"But but but... HILLARY!!!", then you lost the argument before you even began.
Considering two recent botches with lethal injection, I would replace it with carbon monoxide, which is simple, inexpensive, effective, and has no cruelty factor. The criminal just quietly goes to sleep, and that's it.