As bad as execution by lethal injection is, asphyxiation by nitrogen gas is an even less humane way to end human life. Rather than relying on the more palatable pretext of execution by intoxication — as effectively happens through lethal injection — the shift towards nitrogen gas replaces this with pure suffocation, meaning the experience wouldn't even be softened by any kind of anesthesia. This method cannot be morally justified.
While critics may cite a lack of testing behind the use of nitrogen gas, it is clear that this method — if conducted with the same levels of care and diligence as any other execution — could result in a painless loss of consciousness and dignified end of life. As it has the potential to provide a painless means of execution without the use of difficult to source drugs or poisons, or invasive medical procedures, more research must be done into asphyxiation through pure nitrogen so as to remove barriers to its use in executions.