My father was a Ghanaian patriot. He once published a column in our local newspaper under the headline “Is Ghana worth dying for?” and it was clear that his answer was yes. But he also loved Asante, the region of Ghana where he and I both grew up, a kingdom absorbed within a British colony and, then, a region of a new multi-ethnic Republic; a once-kingdom that he and his father also both loved and served.

When he died, my sisters and I found a note he had drafted, and never quite finished, last words of love and wisdom for his children. After a few paragraphs reminding us of our double ancestry — in Ghana and in England — he wrote these words: “Remember, always, that you are citizens of the world.” And he went on to tell us that this meant that wherever we chose to live — and, as citizens of the world, we could choose to live anywhere — we should make sure we left the world “better than we found it.”

My father’s example demonstrates for me, more clearly than any abstract argument, the possibilities that the enemies of cosmopolitanism deny. We cosmopolitans can be patriots, loving our homelands (not the states where we were born but the states where we live); our loyalty to humankind — so vast, so abstract, a unity — does not deprive us of the capacity to care for lives nearer by; the notion of a global citizenship can have a real and practical meaning. Martha Nussbaum’s notion of a cosmopolitan education, and her arguments for it, begin to flesh out further what it would mean, in a practical way, to raise up a generation of cosmopolitans within the American Republic.

But my father’s example also makes me suspicious of one of Nussbaum’s moves: the move that argues against patriotism (my father’s Ghanaian patriotism, which I want to defend) on the grounds that nationality is, as she says, “a morally irrelevant characteristic.” Later on, she argues that in “conceding that a morally arbitrary boundary such as the boundary of the nation has a deep and formative role in our deliberations, we seem to be depriving ourselves of any principled way of arguing to citizens that they should in fact join hands” across the “boundaries of ethnicity and class and gender and race.”

I can only say what I think is wrong here if I insist on the distinction between state and nation. Their conflation is a perfectly natural one for a modern person, because — even after Rwanda, Sri Lanka, India, Bosnia, Azerbaijan . . . — we so readily identify state and nation. But the yoking of nation-state in the Enlightenment was intended to bring the arbitrary boundaries of states into conformity with the “natural” boundaries of nations; the idea that the boundaries of the state could be arbitrary, while the boundaries of the nation were not, is easy enough to grasp, once we are reminded of it.

Not that I want to endorse this essentially Herderian way of thinking: national identities are not “natural” things that grow independently of states and politics. A nation is an “imagined community” of culture and ancestry running beyond the scale of the face-to-face and seeking political expression for itself. And all the nations I can think of that are not coterminous with states are the legacy of older state arrangements; as Asante is in what has become Ghana; as are the Serbian and Croatian nations in what used to be Yugoslavia.

Indeed, I want to emphasize the possibility of distinguishing nation and state to make a point entirely opposite to Herder’s: namely that, if anything is morally arbitrary, it is not the state but the nation. Since human beings live in political orders narrower than the species; and since it is within those political orders that questions of public right and wrong are largely argued out and decided, the fact of being a fellow-citizen of yours — someone who is a member of the same order — is not morally arbitrary at all.

The nation, on the other hand, is arbitrary; but not in a way that permits us to discard it in our moral reflections. It is arbitrary in the root sense of that term; because it is, in the Oxford English Dictionary’s formulation, “dependent upon will or pleasure.” Nations often matter more to people than states: non-existent mono-ethnic Serbia makes more sense than existing multicultural Bosnia; a Hutu (or a Tutsi) Rwanda makes more sense than a peaceful shared citizenship of Tutsi and Hutu; only when Britain or France became nations as well as states did ordinary citizens come to care about being French or British. But notice that the reason nations matter is that they matter to people. Nations matter morally, when they do, in other words, for the same reason that football and opera matter: as things desired by autonomous agents, whose autonomous desires we ought to acknowledge and take account of, even if we cannot always accede to them. If people were to give up their more brutal attachments to the nation — as Nussbaum’s cosmopolitan education would surely make them do — the nation would come to matter less.

States, on the other hand, matter intrinsically: they matter not because people care about them, but because they regulate our lives through forms of coercion that will always require moral justification. As Hobbes saw, the state, to do its job, has to have a monopoly of certain forms of authorized coercion: and the exercise of that authority matters even in places where people have no feeling for the state at all.

There is, then, no need for the cosmopolitan to claim that the state is morally arbitrary, in the way that I have suggested the nation is. There are many reasons to think that living in political communities narrower than the species is better for us than would be our engulfment in a single world-state: a cosmopolis of which we cosmopolitans would be not figurative but literal citizens. It is because humans live best on a smaller scale that we should defend not just the state, but the county, the town, the street, the business, the craft, the profession, the family, as communities, as circles among the many circles narrower than the human horizon, that are appropriate spheres of moral concern. (Nussbaum agrees with this when she says that “the student in the United States, for example, may continue to regard herself as in part defined by her particular loves . . . even for her country.”)

We should, in short, as cosmopolitans, defend the right of others to live in democratic states of which they can be patriotic citizens; and, as cosmopolitans, we can claim that right for ourselves. Martha Nussbaum’s global education would not only make us care more than we do about human beings elsewhere, it would provide us with the knowledge to bring that concern respectfully and intelligently to bear in thinking about how our state — and the many narrower and wider associations of which we are a part — should act in relation to others.