[teenyelliott]

Oh, you know the standard talking points. It's not a deterrent, it costs more to kill them than it does to keep them in prison, what if an innocent person is executed, it's cruel and unusual, it's just revenge, blah blah blah.

My sister is anti-death penalty. I hear it all the time. I still insist that it is a rather effective deterrent, because the person who is executed is deterred from ever committing another crime again.

Sometimes karma and natural selection just aren't thorough enough.

[Restorer]

Ted Bundy hasn't killed any 12-year olds recently.

[Strategerist]

I still insist that it is a rather effective deterrent

The above is probably the weakest of all the pro-death penalty arguments. The type of people typically being executed are the sort who rarely think more than 5 minutes ahead. It's really unlikely there's any sort of rational balancing of the punishments vs. the rewards of whatever murder they're committing.