The Roots of American Order
Russell Kirk describes the Hebrew, Greek, Roman, and Christian influence on the American Constitution and American law. Any Christian influence which goes back more than four or five hundred years is Catholic, and many subsequent influences are also Catholic.
(Political Thought of Bellarmine)
The Political Thought of St. Robert Bellarmine by Clement Rager
This is a strong argument that the political thought of St. Robert Bellarmine was formative in the founding documents of the United States. [Link]
The Closing of the Muslim Mind
How did the Moslems lose the intellectual leadership they had exercised in the middle and late Middle Ages? If you think philosophy doesn't matter, this is your chance to learn how much it matters.
The Law of Nations
The 1848 translation should be available from your State Law Library.
This book, once a basic of American legal studies was out of print and is now available again.
Translated from French, this book is not light reading, and, more to the point, is so anti-Catholic that it was placed on the Index of Forbidden Books. So what is it doing here?
Well in fact, and for the good, it strongly influenced the Founding Fathers and was basic to American jurisprudence until the advent of legal positivism at the very end of the nineteenth century. [Legal positivism is the doctrine that the law is the words on the page; before this doctrine, it was always held that a law that is unjust is no law; this was the basis for Jury Nullification.]
Except for its specific anti-Catholicism, obvious in the footnotes, it contains much of the political thought of St. Robert Bellarmine through the lens of the Catholic-friendly philosopher Leibniz and his unfriendly disciple DeVattel. In particular, it argues for a sisterly relationship between nations, not a relationship of brute competition.
This volume may be another source of the Bellarmine influence amply described by Rager. Remember that many of the Founding Fathers were quite anti-Catholic and would have closed their doors to a "Papist" teaching, but Catholic thought seems to have come by in the window anyway.
This discussion of the just order of life according to traditional Catholic theology, -- including just war -- clarifies the traditional Catholic teaching in these difficult areas.