Theoretically. In practice it's reserved for the unfortunate souls who happen to be born in the most racist parts of the US with the most tough-on-crime attitudes and corrupt policing. And then some of them are just innocent, too.

The problem with death is you can't undo it. If you mess up, including systemic mess ups, it's over.

> where the criminal did actually think it through

Until we can get into the criminal's brain we can't know the extent to which they thought it through.

We're just basically saying, "Anybody would know that they shouldn't kill somebody and it seems like they probably thought about killing this person before they did it."

I doubt there's going to be a stat that satisfies you here, but this one is interesting:

https://deathpenaltyinfo.org/facts-and-research/murder-rates...

I haven't ever seen non-anecdotal evidence (flimsy or otherwise) that makes me think the death penalty acts as a deterrent.