Part 2 concerns the dispensation of law in relation to offensive and defensive force; the nature of political liberty; and the relationship of liberty to taxation. Book 9 considers the defensive capabilities and stratagems of the three governments. Republics, for instance, commonly form a federation in which “many political bodies consent to become citizens of the larger state they want to form” (131). This confederacy is useful because it has the external power of a monarchy but the internal virtue of small governments. Monarchies, which are larger in scope, are inhabited by a spirit of “war and expansion” (132). It protects itself along the frontiers of its territory. Despotic regimes, which are generally even more massive in territorial scope than monarchies, leave the farther reaches of their empires to ruin. Montesquieu writes, “This state does to itself all the ill that could be done by a cruel enemy, but an enemy that could not be checked” (134).

The right of nations, i.e., the law governing international relations, dictates the dispensation of offensive force, the subject of Book 10. States have the right to wage war, Montesquieu writes, in self-defense—but war must be conducted within a strict code in accordance with the rights of nations: “When that right is based on arbitrary principles of glory, of propriety, of utility, tides of blood will inundate the earth” (139).