Article — Noldin, Summa of Moral Theology
Article First. On the Ruler
310. His obligations. 1. Rulers are bound to procure the common good while preserving the liberty of individuals; therefore they must first know wherein the true good of society, namely the temporal happiness which they ought to promote, consists.
They are bound to avert temporal evils and dangers as far as can be done, such as wars, whether with outsiders or civil wars; sects which overturn the foundations of society, as socialism and masonry, etc.; crimes which turn to the damage of the common good, etc.
They are bound to commit public offices to worthy and suitable men, but to remove the evil and inept from them.
They are bound to administer justice without acceptance of persons.
They are bound to preserve the due relation to the Church, to protect her rights, and to help her so that she may obtain her end more easily and more abundantly.
Moreover, it will be more useful to indicate some little works which treat this matter excellently:
a. St. Thomas, De regimine principum ad regem Cypri, Opusc. XVI.
b. Cardinal Bellarmine, De officio principis christiani ad serenissimum principem Wladislaum, Sigismundi III. regis filium.
c. De Ponte-Brandis, Der Weg zur Vollkommenheit fur die hoheren und hochsten Stande in der Gesellschaft (Regensburg: Manz, 1860).
d. W. E. Ketteler, Die Pflichten des Adels (Mainz: Kirchheim, 1868). This is a version of the little work of St. Thomas, or rather of Guil. Peraldus, De eruditione principum.
e. John Mariana, De rege et regis institutione libri tres. Ad Philippum III. Hispaniae regem catholicum. A work otherwise excellent, if he had not defiled it by the doctrine on tyrannicide.
f. The encyclical letters of our most holy lord Leo XIII, Immortale Dei, 1 Nov. 1885, and Libertas, 20 Jun. 1888.