Article 1, Section 8, Clause 11
William Blackstone, Commentaries 1:249--511765
III. Upon the same principle the king has also the sole prerogative of making war and peace. For it is held by all the writers on the law of nature and nations, that the right of making war, which by nature subsisted in every individual, is given up by all private persons that enter into society, and is vested in the sovereign power: and this right is given up not only by individuals, but even by the intire body of people, that are under the dominion of a sovereign. It would indeed be extremely improper, that any number of subjects should have the power of binding the supreme magistrate, and putting him against his will in a state of war. Whatever hostilities therefore may be committed by private citizens, the state ought not to be affected thereby; unless that should justify their proceedings, and thereby become partner in the guilt. Such unauthorized voluntiers in violence are not ranked among open enemies, but are treated like pirates and robbers: according to that rule of the civil law; hostes hi sunt qui nobis, aut quibus nos, publice bellum decrevimus: caeteri latrones aut praedones sunt. And the reason which is given by Grotius, why according to the law of nations a denunciation of war ought always to precede the actual commencement of hostilities, is not so much that the enemy may be put upon his guard, (which is matter rather of magnanimity than right) but that it may be certainly clear that the war is not undertaken by private persons, but by the will of the whole community; whose right of willing is in this case transferred to the supreme magistrate by the fundamental laws of society. So that, in order to make war completely effectual, it is necessary with us in England that it be publicly declared and duly proclaimed by the king's authority; and, then, all parts of both the contending nations, from the highest to the lowest, are bound by it. And, wherever the right resides of beginning a national war, there also must reside the right of ending it, or the power of making peace. And the same check of parliamentary impeachment, for improper or inglorious conduct, in beginning, conducting, or concluding a national war, is in general sufficient to restrain the ministers of the crown from a wanton or injurious exertion of this great prerogative.
IV. But, as the delay of making war may sometimes be detrimental to individuals who have suffered by depredations from foreign potentates, our laws have in some respect armed the subject with powers to impel the prerogative; by directing the ministers of the crown to issue letters of marque and reprisal upon due demand: the prerogative of granting which is nearly related to, and plainly derived from, that other of making war; this being indeed only an incomplete state of hostilities, and generally ending in a formal denunciation of war. These letters are grantable by the law of nations, whenever the subjects of one state are oppressed and injured by those of another; and justice is denied by that state to which the oppressor belongs. In this case letters of marque and reprisal (words in themselves synonimous and signifying a taking in return) may be obtained, in order to seise the bodies or goods of the subjects of the offending state, until satisfaction be made, wherever they happen to be found. Indeed this custom of reprisals seems dictated by nature herself; and accordingly we find in the most antient times very notable instances of it. But here the necessity is obvious of calling in the sovereign power, to determine when reprisals may be made; else every private sufferer would be a judge in his own cause. And, in pursuance of this principle, it is with us declared by the statute 4 Hen. V. c. 7. that, if any subjects of the realm are oppressed in time of truce by any foreigners, the king will grant marque in due form, to all that feel themselves grieved. Which form is thus directed to be observed: the sufferer must first apply to the lord privy-seal, and he shall make out letters of request under the privy seal; and, if, after such request of satisfaction made, the party required do not within convenient time make due satisfaction or restitution to the party grieved, the lord chancellor shall make him out letters of marque under the great seal; and by virtue of these he may attack and seise the property of the aggressor nation, without hazard of being condemned as a robber or pirate.
The Founders' Constitution
Volume 3, Article 1, Section 8, Clause 11, Document 1
The University of Chicago Press
Blackstone, William. Commentaries on the Laws of England: A Facsimile of the First Edition of 1765--1769. Chicago: University of Chicago Press, 1979.
Easy to print version.