Paul Copan's "Is Yahweh a Moral Monster?" presents what struck me, on my first exposure to it, as a relatively novel (to me, anyway) thesis defending God as presented in the Hebrew scriptures from the charge of genocide. He claims that the commands to wipe out Canaan and not leave anyone standing, including women, children, and even livestock are hyperbole and that such expressions were commonly used to indicate a severe attack but did not literally mean that no one at all would survive.
I was a bit hesistant to rely on such a view, because it seemed to be to require more evidence than Copan gave, and there are certainly some occurrences when the expression in question simply cannot mean what Copan wants it to mean, e.g. when Saul is roundly condemned by Samuel in I Sam 15 for not fully carrying out the wiping out of the Amalekites. Saul's failure in that chapter was precisely his willingness to leave some alive, as Wes Morriston pointed out in the comments on Robert Gressis' Prosblogion posting on this last year. That objection struck me as decisive.
It occurred to me very recently, however, that Morriiston's objection doesn't quite do it. I'm still a little skeptical of Copan's thesis without more evidence than I've seen, but I'm not sure anymore that Morriston's objection really defeats the thesis. Consider the following version of Copan's claim. There's the literal meaning of the expression to wipe out everyone and everything. Saul did not do that. He spared Agag and the best of the livestock. Copan could then come along and point out that the passage doesn't include in Saul's failure that he spared women and children, for example. So it's compatible with what the text says that (a) Saul did wipe out all the women and children (and spared just Agag and the best animals) and that (b) Saul didn't wipe out all the women and chilfdren (but never was supposed to kill all of them, just all of the animals and King Agag).
So I'm not sure anything in I Sam 15 disproves Copan's thesis. Saul did sin, according to I Sam 15, by sparing Agag and the best livestock. But it may well have been that Agag and the livestock should have been killed according to the correct Copan-modified translaton or paraphrase of whatever the hyperbolic command really insisted on. In other words, Saul really should have killed Agag and these animals according to the command of God, but that doesn't mean he literally was expected to wipe out the whole Amalekite people. So I don't think I Sam 15 is really a counterexample to Copan's proposal.