I've made my case that I think this guy is not worth the pay and trouble internally with the CEO; while he's not a key hire, I certainly am. And how did the CE

I've made my case that I think this guy is not worth the pay and trouble internally with the CEO; while he's not a key hire, I certainly am. And how did the CEO respond? That's one of the missing pieces from the story-- an outside evaluation of the value of this guy. If he's as useless as you say, why is your co-founder so attached to keeping him? Could it be that he is providing some significant value to the company that you're not aware of? If I were in your shoes, I'd modify your working list a bit, and go with 3B) Have a heart to heart with the CEO to find out what is really going on here. If that doesn't clear things up, I'd go to 2B) Make a case to the board, to try to get some motivation to find a better fit. I wouldn't threaten to leave, or trash him to the board. Neither one is a productive move. Your nemesis obviously has a high opinion of his skills and value. If that's the case, there should be some clear objectives and timeframes he's expected to hit. That should make these discussions a bit easier.