Dylann Roof sentenced to death for Charleston church massacre

It's more expensive because of the safeguards around appeals and making sure you have the right guy and have given due process.

For a conservative look at the reasons and the process: https://www.themarshallproject.org/...-the-death-penalty-is-becoming-more-expensive

The underlying reasoning for being cautious and thorough with appeals have to do with our sense of due process and our experience and history with hasty and bad convictions. No one wants to find out they lynched the 19 year old maniac who came out and confessed and did interviews about how he hated all the people he gunned down and would do it all again only to find out later that DNA showed a 43 year old businessman shot up the joint when investigating him doing a second heinous crime like it 5 years later. For all kinds of reasons you don't want a quick show of hands and a lynching of the wrong guy. Some are moral, some are practical like getting sued by the family for negligence by the prosecutor, etc.