It was proper for the poet to say that, because, when he was working out his Atreus, he had to make the words fit the character. But if they mean to adopt it as a principle, that a pledge given to the faithless is no pledge, let them look to it that it be not a mere loophole for perjury that they seek.
What is perjury?
107 Furthermore, we have laws regulating warfare, and fidelity to an oath must often be observed in dealings with an enemy: for an oath sworn with the clear understanding in one's own mind that it should be performed must be kept; but if there is no such understanding, it does not count as perjury if one does not perform the vow. For example, suppose that one does not deliver the amount agreed upon with pirates as the price of one's life, that would be accounted no deception—not even if one should fail to deliver the ransom after having sworn to do so; for a pirate is not included in the number of lawful enemies, but is the common foe of all the world; and with him there ought not to be any pledged word nor any oath mutually binding. 108 For swearing to what is false is not necessarily perjury, but to take an oath "upon your conscience," as it is expressed in our legal formulas, and then fail to perform it, that is perjury. For Euripides aptly says:
"My tongue has sworn; the mind I have has sworn no oath."
Oaths made to an enemy as binding as treaties.
But Regulus had no right to confound by perjury the terms and covenants of war made with an enemy. For the war was being carried on with a legitimate, declared enemy; and to regulate our dealings with such an enemy, we have our whole fetial[CE] code as well as many other laws that are binding in common between nations. Were this not the case, the senate would never have delivered up illustrious men of ours in chains to the enemy.
109 XXX. At vero T. Veturius et Sp. Postumius cum iterum consules essent, quia, cum male pugnatum apud Caudium esset, legionibus nostris sub iugum missis pacem cum Samnitibus fecerant, dediti sunt iis; iniussu enim populi senatusque fecerant. Eodemque tempore Ti. Numicius, Q. Maelius, qui tum tribuni pl. erant, quod eorum auctoritate pax erat facta, dediti sunt, ut pax Samnitium repudiaretur; atque huius deditionis ipse Postumius, qui dedebatur, suasor et auctor fuit.
Quod idem multis annis post C. Mancinus, qui, ut Numantinis, quibuscum sine senatus auctoritate foedus fecerat, dederetur, rogationem suasit eam, quam L. Furius, Sex. Atilius ex senatus consulto ferebant; qua accepta est hostibus deditus. Honestius his quam Q. Pompeius, quo, cum in eadem causa esset, deprecante accepta lex non est. Hic ea, quae videbatur utilitas, plus valuit quam honestas, apud superiores utilitatis species falsa ab honestatis auctoritate superata est.
110 At non debuit ratum esse, quod erat actum per vim.—Quasi vero forti viro vis possit adhiberi.