The modern opposition of universal/timeless vs. national/historical (Enlightenment vs. Romanticism) is really another manifestation of rationalism, namely of the denial of the transcendent. If truth transcends us, ideals must always find new partial historical realizations.
Thus, from a more traditional perspective ("Christendom") each "nation" corresponded to one implementation of a universal, inexhaustible call (embodied by the founding saint/king/evangelizer) which could take many historical forms while remaining universal.
By contrast, the modern idea of nation is, as DN says, a reduction of the idea of tradition, because it no longer refers to an ideal (which by nature is universal, although amenable to many "incarnations") but simply to a historical past that does not carry a universal value.
Vice versa after the Enlightenment universality claim to be exhaustive but in reality is completely abstract (abstract rights, abstract knowledge, abstract laws) an therefore it is no longer able to generate nations, so to speak.
