[throwawayboise]

Sentences are imposed by judges, so if a judge in a given county has a hard-on for death sentences, you'll see more of them in that county.

[gustavo-fring]

Not just that but some judges are elected and research (I know, no cites) shows that elected judges get tougher in election years.

Now you're making me wonder if they controlled for elected judges.

[khuey]

The death penalty requires a jury to vote for it (usually unanimously) in most if not all US states.

[SpicyLemonZest]

All states nowadays, since Ring v. Arizona requires it.

[sillysaurusx]

It would be interesting to see a breakdown of whether male vs female judges have more or less death penalty sentences.