Article 1, Section 8, Clause 11

Document 6

James Wilson, Legislative Department, Lectures on Law

One great end of the national government is to "provide for the common defence." Defence presupposes an attack. We all know the instruments by which an attack is made by one nation upon another. We all, likewise, know the instruments necessary for defence when such an attack is made. That nation, which would protect herself from hostilities, or maintain peace, must have it in her power--such is the present situation of things--to declare war. The power of declaring war, and the other powers naturally connected with it, are vested in congress. To provide and maintain a navy--to make rules for its government--to grant letters of marque and reprisal--to make rules concerning captures--to raise and support armies--to establish rules for their regulation--to provide for organizing, arming, and disciplining the militia, and for calling them [Volume 3, Page 95] forth in the service of the Union--all these are powers naturally connected with the power of declaring war. All these powers, therefore, are vested in congress.

As the law is now received in England, the king has the sole prerogative of making war. On this very interesting power, the constitution of the United States renews the principles of government, known in England before the conquest. This indeed, as we are told by a well informed writer, may be accounted the chief difference between the Anglo-Saxon and the Anglo-Norman government. In the former, the power of making peace and war was invariably possessed by the wittenagemote; and was regarded as inseparable from the allodial condition of its members. In the latter, it was transferred to the sovereign: and this branch of the feudal system, which was accommodated, perhaps, to the depredations and internal commotions prevalent in that rude period, has remained in subsequent ages, when, from a total change of manners, the circumstances, by which it was recommended, have no longer any existence.

The Founders' Constitution
Volume 3, Article 1, Section 8, Clause 11, Document 6
http://press-pubs.uchicago.edu/founders/documents/a1_8_11s6.html
The University of Chicago Press

The Works of James Wilson. Edited by Robert Green McCloskey. 2 vols. Cambridge: Belknap Press of Harvard University Press, 1967.