or “prince;” for it is plain that it is not lawful for every prince or judge whatsoever to wage war.  The solution of this difficulty, according to St. Thomas (ubi supra,) and Cajetanus (ibi and in Summa, ch.  Bellum), and Castro (De justa haereticorum punitione lib. 2, c. 4), is that by “public person” in the present case is understood the one who in his government depends not on another; such are the kings of Spain and France, also some free commonwealths, as Venice, Florence, and Ferrara:  these have authority, without recourse to another, to wage war.  But those princes and states whose government is not sovereign may not levy war without authority from their superior; and so the lords of Castilla and the viceroys and governors appointed by our king Philippus may not without a warrant make war.

What is said applies not when war is waged for defense against enemies, but in other circumstances; for if it is for defense, such war is permitted to any governor or king, as the authors say, because vim vi repellere licet; [11] and thus the viceroys and governors of the Indias have authority to levy war against disturbers of the peace and quiet of the states of which they are in charge, without necessity of resorting to his Majesty for permission.

The second condition of righteous war is that the cause for which it is waged shall be a just one, as St. Thomas says:  “Those upon whom war is waged deserve it for the offenses that they have committed, and the grievances that they have inflicted upon the one who makes war on them.”  Thus says St. Augustine (lib. 83. Quaestionum super Josue, 9. 10), and Gratian quotes him (23, q. 2, c. Dominus noster):  Justa autem bella solent definiri quae ulciscuntur injurias, si gens vel civitas plectenda est, quod vel vindicare neglexerit quod a suis improbe factum est, vel reddere quod per injuriam ablatum est. [12] And as this injury and grievance may be of many kinds, so too, many and various are the just causes of war; but we will consider here only those which make for the matter in hand, confirmed by the authority of Scripture.

The first ground of a righteous war may exist when one is hindered from doing what he may by right do.  This is matter of natural and divine law and on this ground Julius Caesar, as Lucan represents him (lib. 1), made defense of his conduct in waging war against the Roman state—­viz., that the state had blocked to him, a Roman citizen, the route to Rome; and so he said, arms in hand, Omnia dat qui justa negat. [13] On this ground, as St. Augustine says (in Quaest.  Num. q. 43), [14] the children of Israel justly made war on the kings of the Amorites (Ut legitimum, c. 21), for having withstood their passage through their country when they were on their way to the promised land, although the Israelites had given assurance that they would do no damage to the lands, the crops, or the vineyards of the Amorites.