The botched execution of an Oklahoma inmate is certain to fire up the debate over what constitutes cruel and unusual punishment — the phrase written into the U.S. Constitution and defined by the courts, piece by piece, over two centuries.

Convicted killer Clayton Lockett, 38, began writhing, clenching his teeth and straining to lift his head off the pillow Tuesday evening after he was supposedly rendered unconscious by the first of three drugs in the state’s new lethal injection combination.