The ninth book of Livy may be consulted on the distinction between treaties and engagements, where the historian informs us, that treaties are those contracts, which are made by the express authority of the sovereign power, and in which the people invoke the divine vengeance on their heads, if they violate their engagements. Among the Romans the persons employed in declaring war and making peace, were in the conclusion of these solemn treaties, always accompanied by the principal herald, who took the oath in the name of the whole people. A sponsio, or ENGAGEMENT, is what was made by persons, who had no express commission for that purpose from the sovereign power, and whose acts consequently required a further ratification from the sovereign himself.[40]
The Senate of Rome, we are informed by Sallust, judged very properly in passing a decree, that no treaty could be made without their consent and that of the people. Livy relates that Hieronymus, king of Syracuse, having entered into a convention with Hannibal, sent afterwards to Carthage to have it converted by the state into a league. For which reason Seneca the elder has said, applying the expression to persons invested with a special commission for that purpose, that a treaty, negotiated by the general, binds the whole of the Roman people, who are supposed to have made it.
But in monarchies, the power of making treaties belongs to the king alone, a maxim which the language of poetry, no less than the records of history, shews to have been held in all ages. Euripides, whose sentiments are always conformable to nature, and popular opinion, in his Tragedy of the Suppliants, says, "It rests with Adrastus to take the oath, to whom, as sovereign, the sole right of binding the country by treaties belongs."
No subordinate magistrates have such a power of binding the people; nor will the acts of a smaller portion bind the greater, an argument used in favour of the Romans against the Gauls. For there was a majority of the people with Camillus, the dictator.
But it remains to be considered how far the acts of those, who have engaged for the people, without any public authority, are binding. Perhaps it may be said that the contracting parties have discharged their responsibility when they have done all in their power towards the fulfilment of their obligation. That might be the case in promises, but the obligation in public contracts is of a stricter kind. For the party contracting requires something in return for the engagements he makes. Hence the civil law, which rejects all promises made by one person for the performance of some act by another, renders him who engages for the ratification of a thing liable to pay damages and interest.
IV. The most accurate distinction in treaties, is that which makes the foundation of some rest purely upon the law of nature, and others upon the obligations, which men have either derived from the law of nature, or added to it. Treaties of the former kind are, in general, made, not only between enemies, as a termination of war; but in ancient times were frequently made, and, in some degree, thought necessary among men in the formation of every contract. This arose from that principle in the law of nature, which established a degree of kindred among mankind. Therefore it was unlawful for one man to be injured by another. And this natural justice universally prevailed before the deluge. But after that event, in process of time, as evil dispositions and habits gained ground, it was by degrees obliterated. So that one people's robbing and plundering another, even when no war had been commenced or declared, was deemed lawful. Epiphanius calls this the Scythian fashion. Nothing is more frequent in the writings of Homer than for men to be asked, if they are robbers? A question, as Thucydides informs us, by no means intending to convey reproach, but purely for information. In an ancient law of Solon's mention is made of companies formed for robbery: and, we find from Justin, that, till the times of Tarquin, piracy was attended with a degree of glory.
In the law of the Romans it was a maxim, that nations, which had not entered into terms of amity, or into treaties with them were not to be considered as enemies. But if any thing belonging to the Romans fell into their hands, it became theirs; or any citizen of Rome, taken by them, became a slave; and the Romans would treat any person belonging to that nation, in the same manner. In this case the right of postliminium[41] is observed. So at a remote period, before the times of the Peloponnesian war, the Corcyraeans were not considered as enemies by the Athenians, though there was no treaty of peace subsisting between them, as appears from the speech of the Corinthians given by Thucydides. Aristotle commends the practice of plundering barbarians, and in ancient Latium an enemy signified nothing but a foreigner.
In the class of treaties referred to in this section may be ranked those made between different states for the mutual preservation of the rights of hospitality and commerce, as far as they come under the law of nature. Arco makes use of this distinction, in his speech to the Achaeans, as reported by Livy, where he says he does not require an offensive and defensive alliance, but only such a treaty as may secure their rights from infringement by each other, or prevent them from harbouring the fugitive slaves of the Macedonians. Conventions of this kind were called by the Greeks, strictly speaking, PEACE in opposition to TREATIES.
V. Treaties founded upon obligations added to those of the law of nature are either equal, or unequal. Equal treaties are those, by which equal advantages are secured on both sides. The Greeks call them ALLIANCES, and sometimes alliances upon an equal scale. But treaties of the latter kind are more properly leagues than treaties, and where one of the parties is inferior in dignity, they are called INJUNCTIONS, or INJUNCTIONS ANNEXED TO COVENANTS. Demosthenes in his speech on the liberty of the Rhodians says, all nations ought to guard against forming such leagues, as approaching too near to servitude.
Treaties of both kinds, whether of peace or alliance are made from motives of some advantage to the parties. By equal treaties of peace, the restoration of prisoners, the restoration or cession of conquered places, and other matters providing for its due maintenance, are settled, a subject that will be more fully treated of hereafter, in stating the effects and consequences of war. Treaties of alliance upon equal conditions relate either to commerce, or to contributions for the joint prosecution of a war, or to other objects of equal importance. Equal treaties of commerce may vary in their terms. For instance it may be settled that no duties shall be imposed upon the goods of the subjects, belonging to each of the contracting powers: or that the duties upon their respective commodities shall be lower than the duties upon those of any other nation. The first of these examples may be found in an ancient treaty between the Romans and Carthaginians, in which there is a clause, making an exception of what is given to the notary and public crier. Or it may be settled that no higher duties than those existing at the time the treaty is made shall be imposed, or that they shall not be augmented beyond a certain rate.