Death penalty supported even with "the inevitability of caprice and mistake".

Glenn Reynolds, Instapundit

Instapundit:

"The best argument against the death penalty, of course, is what Charles Black called “the inevitability of caprice and mistake.” But that argument, taken seriously, is an indictment of the entire criminal-justice system, not just the death penalty. It may be a valid indictment, but few are willing to go that far.    The worst argument against the death penalty, of course, is that it’s somehow awful for the state to kill people. Nation-states are all about killing people". 

Should no one be given a speeding ticket because some tickets will be wrongly charged? Should no one go to jail for kidnapping because some will be wrongly convicted?   If "being alive"is so radically different from other rights, then rationed health care and publicly funded abortion-on-demand are as wrong as the death penalty.  Nation states have alway succeeded by owning the rights to violence within their sway.

Support for the death penalty:
The predicted sea change in public perceptions of the death penalty didn't happen (after Cameron Todd Willingham (was) executed in 2004 for setting the fire that killed his three young children. Willingham was convicted because of forensic testimony from fire officials that arson experts call junk science.) According to Gallup polling, support for the death penalty dropped just a point between 2009 and 2010, from 65 percent to 64 percent, well within the margin for error.

An extensive review of potential flaws in testimony, DNA and police procedure is offered by Radley Balko at the Huffington Post.