We’re trying to walk this line of deterrence without a full blown regional conflagration. Do we really want a military dictator who’s already on thin ice with his population openly participating in aggression against other Arabs? My bet - we get some quiet support from SA in the form of intel about best targets, since they’re already so involved in the conflict against the houthis.

Egypt participating openly is a recipe for domestic unrest in that country, and while we’re not fans of military dictatorships, I think we’d prefer that to a successful Islamist revolution there. So, consistent with keeping this whole thing from exploding regionally, I don’t think we want Arab countries participating in this open military action.