Capital Punishment as a Moral Duty

Thane Rosenbaum, the author of an awful book, The Myth of Moral Justice, has returned with the threat of a new book, on vengeance, and an op-ed in today's NYT.  He suggests that capital punishment is morally appropriate, that killing in revenge is a moral duty. and that the state's failure to avenge (because of "procedural errors" and reasonable doubt) is a breach of the social contract, justifying vigilantism.  There is nothing in the op-ed about the conviction of innocents, racial disparities in sentencing, or the immorality of cold-blooded killing by the state.