The anti-death penalty crowd will argue that there is some objection to every form of execution: hanging can actually decapitate the criminal if the drop is too long or the person is too heavy, or it may not snap the neck thoroughly if not long enough or the person is too light. Firing squad may not kill with the first volley, leaving the victim to be dispatched with a coup de grace. Gas suffocates. The "chair" burns the criminal and may require several agonizing jolts to stop the heart. The guillotine has never found favor in this country; we're not as bloodthirsty as the French.
Then there are all the variations on gibbeting, impalement, beheading, burning, etc.. All have their drawbacks, and some are nothing more than thinly disguised sadism. A clinical, medically sound lethal injection is certainly within the constitutional limit on "cruel and unusual."
Guillotine may be messy, but the head is severed before the nerve endings can send pain signals to the brain.
> The point is, even if it takes multiple tries
> to find a vein, that is still not “cruel and
> unusual.”
Well, quite, but that’s not the point you made originally, and that prompted my reply. As to the issue of getting the drop correct, that’s been fixed for quite some time.