It lies in the nature of a clam to attach himself after this fashion, loosely, to the bottom where he finds a living, and he would not be a "good clam and true" if he failed to do so; but the particular spot for which he forms this attachment is not of the essence of the case.

At least, so they say.
It may be, as good men appear to believe or know, that all men of sound, or at least those of average, mind will necessarily be of a patriotic temper and be attached by ties of loyalty to some particular national establishment, ordinarily the particular establishment which is formally identified with the land in which they live; although it is always possible that a given individual may be an alien in the land, and so may owe allegiance to and be ruled by a patriotic attachment to another national establishment, to which the conventionalities governing his special case have assigned him as his own proper nation.

The analogy of the clam evidently does not cover the case.

The patriotic citizen is attached to his own proper nationality not altogether by the accident of domicile, but rather by the conventions, legal or customary, which assign him to this or that national establishment according to certain principles of use and wont.
Mere legal citizenship or allegiance does not decide the matter either; at least not by any means unavoidably; as appears in the case of the Chinese subject under Manchu or Japanese rule; and as appears perhaps more perspicuously in the case of the "hyphenate" American citizen, whose formal allegiance is to the nation in whose land he prefers to live, all the while that his patriotic affection centers on his spiritual Fatherland in whose fortunes he has none but a non-resident interest.

Indeed, the particular national tie that will bind the affections--that is to say the effectual patriotic attachment--of any given individual may turn out on closer scrutiny to be neither that of domicile or of formal legal allegiance, nor that of putative origin or pedigree, but only a reflex of certain national animosities; which may also turn out on examination to rest on putative grounds--as illustrated by a subsidiary class of hyphenate American citizens whose affections have come to be bound up in the national fortunes of one foreign Power for the simple, but sufficient, reason that, on conventional grounds, they bear malice against another equally foreign Power.
Evidently there is much sophistication, not to say conventionalised affectation, in all this national attachment and allegiance.