Texas has a history of executing the disabled and presenting "expert" junk science as evidence. https://www.propublica.org/article/is-texas-still-executing-...
https://www.texastribune.org/2011/04/15/texas-psychologist-p...
Illinois had similar problems with the death penalty, including likely executing innocent people.
Arkansas executed an innocent but convicted person in 2017 who was subsequently cleared by DNA evidence. https://www.psychologytoday.com/us/blog/making-sense-chaos/2...
So it seems the death penalty cannot be enforced if it cannot be investigated or adjudicated with a necessary and sufficient degree of rigor. It also doesn't serve a purpose as a deterrent (criminals aren't smart enough to anticipate outcomes). Furthermore, it makes the society that dispenses it appear governed by a 3rd-world authoritarian regime. Finally, it's an expensive process and a bloodlust spectacle. Better off keeping cretins alive behind bars for the remote possibility of rehabilitation and let them live with themselves rather than giving them an easy out.