Well, that learned him.  And it certainly acted as a deterrent because he never did it again.  But what if he didn’t do it the first time? Just recently a South Carolina resident was exonerated 70 years after he was executed.  And that my friends is why I’m opposed to capital punishment. 
In 1944 George Stinney Jr was arrested for the murder of 7 year old Mary Emma Thames, and 11 year old Betty June Binnicker.  Within 90 days he had been tried, convicted and executed.  His trial lasted 3 hours, the jury deliberated for 10 minutes and 53 days later they executed him sitting on a phone book because he was too small for the electric chair.  He was 14 years old. 
That is what happened to an African American child accused of killing two white children in the Deep South 70 years ago.  But do you think Stinney is the only person, black or white who was executed for crimes they may not have committed? And you can’t undo an execution, you can only apologize.
One thing we have discovered through the years is that our justice system isn’t perfect by any stretch of the imagination, and we have to live with that, but people shouldn’t have to die for it.  