In a traditional war, legality has already been met via law (either through a formal declaration of war or through the limited war powers given to the executive

In a traditional war, legality has already been met via law (either through a formal declaration of war or through the limited war powers given to the executive). There is no need to justify in front of a judge, because the rights have already been granted. But again, you can only kill certain people, also defined by law. You can't just start carpet bombing cities anymore, otherwise, yes, you may very well find yourself in front of a judge (and presumably these cities would consist of foreigners, so yes, there would be a requirement). US courts may not have jurisdiction abroad, but the executor of actions is presumably or will presumably be on American soil at some point.