(b) Aliens are bound by the laws of the country that include them, such as those that regulate public order and the making of contracts.
551. The Obligation of Civil Law.—Civil law, when it has all the conditions of valid law, even if the legislator is non-religious or anti-religious, is obligatory not only before the State, but also before God (i.e., in conscience). This is; (a) by reason of the natural law, of which it is a derivation (see above, 313); (b) by reason of divine positive law, for it is frequently declared in scripture and in the Church’s teaching and practice that lawful authority represents God and must be obeyed for conscience’ sake: “Render to Caesar the things that are Caesar’s” (Matt, xxii 21), “Be subject of necessity, not only for wrath, but also for conscience’ sake” (Rom, xiii. 5).
552. Are subjects obliged to offer themselves for punishment prescribed by law?
(a) If the fault committed was merely juridical (i.e., before the law), the penalty is certainly not obligatory before sentence. Example: Balbus through sheer accident, and without design or negligence, kills a man. If involuntary homicide is punished by imprisonment, Balbus is not bound to give himself up. English common law, it should be noted, presumes a man innocent until proved guilty, and a man cannot be convicted of any degree of homicide on his own confession alone. But he may plead guilty to minor offenses.
(b) If the fault committed was theological (i.e., before God) and the penalty is primitive (i.e., the loss of some right or privilege), the penalty is obligatory in conscience. In Canon Law such penalties are sometimes _ipso facto_, that is, before sentence (e.g., suspension of a cleric); but the civil law, it seems, imposes penalties only after judicial declaration. Example: Titus on account of bribery has forfeited the right to vote; but he has not been declared guilty by court, and hence may continue to use the right of suffrage.
(c) If the fault was theological and the penalty incurred is active (e.g., exile, imprisonment, fine), the penalty is not obligatory before sentence; for it would demand too much of human nature to require that one deliver oneself up to exile, accept confiscation, etc. The apprehension and detention of the guilty is imposed by law as a duty on the police and other officers, not on the guilty.
553. The kind of obligation imposed depends on the will of the lawgiver: (a) he can oblige under pain of sin, or under pain of nullity or punishment; (b) he can oblige under pain of grave sin, or under pain of venial sin.
554. Generally speaking, the legislator is held to oblige under pain of sin in the following cases: (a) when the law is a just determination of the natural law (e.g., the laws that determine ownership); (b) when the law is directly concerned with and necessary to the public good (e.g., laws on national defense in time of war, laws that impose necessary taxation, etc.; see above, 379).
555. The legislator is held not to oblige under sin in the following cases: (a) when the law is enacted as penal, or is prudently regarded as such—as is the case with laws that are of minor importance or that can be enforced without a moral obligation—laws useful rather than necessary; (b) when the law is merely irritant or inhabilitating, the subject is not obliged to omit the act invalidated, but only to suffer the consequence of nullity before the law.
556. In doubt as to the obligation of a law, what is the duty of the subject? (a) If there is doubt concerning its justice, the subject can always observe it with a safe conscience. One may obey an unjust law, until it is judicially declared unjust, if it is not manifestly opposed to divine or human rights. (b) If there is doubt whether a law obliges under sin or not, the subject does not sin directly by non-observance (see 375, 376, 377, 561).