 Since it regulates reproduction, without which human society would cease to exist, the institution of marriage is “the foundation of social life” (DJN VI.1.7; Dufour 1972, Ehrle 1952). Humans are obligated to enter it, though only in a general way that presupposes capacity, opportunity, and other facilitating conditions. Despite being commanded by God – like other natural law obligations – its immediate origins lie in each instance in a consensual pact between basically equal partners (DJN VI.1.12). This holds even where a woman’s (express or tacit) consent – like terms of captivity in general – follows upon (a just) war (DJN VI.1.9, 1.12; VI.3.5–6). Though its end differs from that of the state (reproduction vs. security), the marital unification of wills may establish a hierarchical, quasi-sovereignty relationship between spouses, one of whom agrees to submit to the other’s authority; on the other hand, marriage may have the character of an “unequal confederation,” which also requires diverse but mutual performance (i.e., command and obedience; DJN VI.1.11). What is impermissible in both cases and institutions, however, because of its supposed dysfunctionality for governance, is a divided command or two heads.