I believe that some criminals have no business still having their heads attached. And why on earth would one bother with that lethal injection jiggerypokery, if it is so complicated and liable to malfunction when a guillotine would do?
I respect your opinion here, but want to point out that there are
solid reasons for not using the guillotine.
The real reason for not using the guillotine is the effect on the execution party, not the condemned.
We used to use firing squads, which seem relatively humane, but I don't know their effect on the executioners.
Personally I'm opposed to the death penalty in most cases because in our (american) justice system we have a tendency to convict innocent people, and some even end up on death row. You can't undo an execution if someone turns out to be innocent. You can't give someone back the years they spent in jail either, but at least they're not dead.
Another issue is that
the death penalty in the USA is more expensive than life without parole. (This was the first google result. Google also suggested a Forbes article, but when I clicked it, it took me to Forbes' homepage so I guess Forbes doesn't care if anyone actually reads their stuff)
In the case of someone like the boston marathon bomber, or any other mass murderer or terrorist for whom there is incontrovertible evidence of their guilt, I am still pro-execution.
I am also in favor of housing terrorists, people who support(ed) ISIS, etc, separately from other inmates, so that they don't have the opportunity to convert them to their ideology (which has been a problem in Europe). Also nazis and such, because we don't need that to spread either, but apparently there are a lot of nazis in our prisons already.