My answer to your question about the transferability of an institutional model from one country to another is yes and no.
No, if we simply try to transfer the institutional mechanics, so to speak, e.g., regarding our Western democracies, the electoral mechanism. Yes, if we look at the underlying ideas of a political experience.
The tragedy, as you pointed out yourself, is that we too might tend to forget the latter, laying all the stress on the first. Hence the creeping civil war.
One of the few authors who had something serious – should I say scientific? – to say in political matters, the Notre Dame Scottish professor Alasdair MacIntyre, laid a strong stress on the need of recovering an ethic, which is also a psychology, of the virtues.
For whomever is reading who is not inside such matters, I am speaking of the four cardinal virtues, already identified by Plato and Aristotle: prudence, fortitude, temperance and justice; and the three theological virtues, identified by Christian theology, but I think of equal universal import as the other: faith, hope and charity.
However, MacIntyre remarks that the doctrine of the cardinal virtues was classically tied with a certain model of man fit for a certain society: that of the Greek city state, the polis. So he asks himself how could they be transferred to men of a different kind of society, thus being made universal as for example in St. Thomas Aquinas' Summa.
Now I go by memory, and I haven't verified MacIntyre's answer. It seems to me to be something of the kind: because St. Thomas makes them proper for any human intercourse, so much more if it involves people coming from different human groups. The way I understand it, this necessarily requires complementing the cardinal virtues with the theological ones.
Calling faith, hope and charity "theological" doesn't mean that they depend on a religious doctrine, which only confers them their ethical validity. It is quite the reverse: they are rooted in any human intercourse, and therefore it's them that measure the religious and political validity of a doctrine, its "catholicity".
Now, back to America. Two things.
First: one of my teachers, Will Herberg, strongly stressed America being a land of immigrants: i.e., coming close to realize the situation envisioned by St. Thomas, where naked human intercourse demands the full set of the four and three virtues.
Second: it wasn't, though, made by the convergence of peoples of any kind whatsoever (as POTUS suggested in a speech of his) but of peoples who, for all their ethnic differences, somehow knew of the virtues required by the American experience.
That's why some peoples seem fit for America, like, more recently, Koreans or Vietnamese; while others seem unfit, like, alas, Islamics (with all the due qualifications of the case).
Your work on America, dear LD, is important, and needs to be carried on, precisely because both liberals and conservatives tend to think in abstract terms, detached from the core of the American experience. This needs to be unearthed in its most characteristic manifestations, to bring it consciously to philosophy.