The death penalty is not simply a state-by-state issue.
Besides the existence of a federal and military death penalty, the federal court system, including the US Supreme Court, deals with Constitutional issues related to the death penalty in states constantly, and has imposed various restrictions on its usage. SCOTUS has also been on an excruciatingly slow but clear path towards total nationwide abolishment.
There is very little in the US that can be treated as purely state-by-state, and so long as the 8th and 14th amendments exist, capital punishment definitely isn't one of them.
It's like saying State Insurance isn't a simple state issue because there could be intervention by the feds. Of course, but de-facto, it's a state issue and the Feds have their own purview for things like the military and treason, etc.
But, if a state wanted to eliminate it, they could, so long as their legislature or judiciary so decided. So it is a state by state issue, by and large.
[PS] I think allowing things to be done state by state actually help in the end to get the whole nation to agree on things which as a whole it might not without states or a state 'testing the waters' as it were. Eventually I see all states eliminating capital punishment, and I think being able to refer to states that have and show that it has not resulted in higher murder rates post elimination is a good thing. Same for pot laws and same sex marriage laws. In this big republic, given that we're not a strictly civil law, I think this bit by bit helps out, in the long run.
No, you're missing the point. The nation as a whole permits the death penalty to continue, even if some political subdivisions choose not to impose it themselves.
The idea of 50 sovereign states doing their own thing is merely a convenient fiction for those who don't want the murders conducted in their name to bother their conscience.
And it falls apart completely when you remember, the federal government sentences people to death, too, not just states. America conducts state-sponsored murder. Not even the 50-state fiction shields anyone from that reality.
Edit Re PS: Speaking of being technical... You're focusing on the mechanisms. I'm very familiar with the mechanisms, and I don't care about them. I care about the result. The result is we remain one of forty countries, almost all of which we hypocritically lambast for their human rights records, to retain the death penalty. No amount of procedural justification will change that, nor will it reduce our moral responsibility.
The federal government does still utilize the death penalty, but it's very rare these days. Only three times since 1963, whereas Texas has executed 500 people since 1982.
Besides the existence of a federal and military death penalty, the federal court system, including the US Supreme Court, deals with Constitutional issues related to the death penalty in states constantly, and has imposed various restrictions on its usage. SCOTUS has also been on an excruciatingly slow but clear path towards total nationwide abolishment.
There is very little in the US that can be treated as purely state-by-state, and so long as the 8th and 14th amendments exist, capital punishment definitely isn't one of them.