Philosophy may study political questions at many different levels of generality and abstractness, all valuable and significant. It may ask why it is wrong to attack civilians in war either from the air by ordinary bombs or by atomic weapons. More generally, it may ask about just forms of constitutional arrangements and which kinds of questions properly belong to constitutional politics. More generally still, it may ask whether a just and well-ordered constitutional democracy is possible and what makes it so. I don’t say that the more general questions are the more philosophical, nor that they are more important. All these questions and their answers, so far as we can find them, bear on one another and work together to add to the knowledge of philosophy.