"Is Capital Punishment Pro-Life?"

Tom Neven asks the question, at First Things. (Please read the piece before writing an outraged "of course not!" comment.)  He concludes with this:

[I]t is out of my deep respect for human life, created in God’s image, that I think the only just punishment for a cold-blooded murder is that that life be avenged as God commands. But being human and fallible, I urge the greatest caution and certainty before doing so.

My view is that political communities should reject capital punishment, in part because such a rejection can (though we should not pretend it always, or even usually, does) provide a witness to the dignity of the human person.  I do not think, though, the question is an easy one.