Article 2, Section 2, Clause 1
St. George Tucker, Blackstone's Commentaries 1:App. 329--311803
1. The first is, That he shall be commander in chief of the army and navy of the United States, and of the militia of the several states, when called into the service of the United States. A power similar to that of the king of England, and of the stadtholder of Holland, before the late revolution; yet qualified, by some important restrictions, which I believe were not to be found in either of those governments. As, first; he cannot make rules for the regulation and government of the army and navy, himself, but they must be governed according to regulations established by congress. But notwithstanding this provision in the constitution, the act of 5 Cong. c. 74, authorised the president to make and establish such rules for training and disciplining the corps of volunteers, authorised to be raised by that act, as should be thought necessary to prepare them for actual service. . . . Secondly; the president of the United States hath not an unqualified right to appoint what officers he pleases; but such appointment (if there be no provision to the contrary made by law) must be made with the advice and consent of the senate: a restriction, perhaps of little importance, whilst the right of nomination, in all cases, and the right of filling up vacancies during the recess of the senate, remain uncontrollably in his power; to which may be added, the authority given him by the act for raising a provisional army, (and perhaps some others) to appoint such officers as he may think proper in the recess of the senate; "the appointment of field officers to be submitted to the advice and consent of the senate, at their next subsequent meeting;" leaving the appointment of all officers of inferior rank to the discretion of the president, alone. The stadtholder of Holland derived his power and influence in great measure from a similar authority. . . . A third and infinitely more important check, than either of the former, so long as elections continue as frequent, as at present, is, that no appropriation for the support of an army can be made for a longer term than two years, the period for which congress is chosen. This puts it in the power of the people, by changing the representatives, to give an effectual check to the power of the executive at the end of that period. . . . In England, the power of raising armies, ad libitum, is vested in the king, though he is said to be dependent upon the parliament for their support; a supply bill, which is always limited to one year, passes accordingly, every session. Should it be refused, (a case which I believe has not happened for more than a century), a dissolution would pave the way, immediately, for a more complying parliament. Fourthly; the militia of the several states, though subject to his command when called into actual service, can only be called into service by the authority of congress, and must be governed [Volume 4, Page 11] according to law: the states, moreover, have the right of appointing the officers, and training the militia, according to the discipline prescribed by congress, reserved to them by the constitution. But we have seen in what manner this very important clause has been evaded, by at acts of 5 Cong. c. 64 and 74, authorising the president to accept companies of volunteers, and to appoint their officers, &c. A precedent, which if it be drawn into authority and practice in future, may be regarded as superceding every part of the constitution, which reserves to the states any effectual authority over their militia.
The Founders' Constitution
Volume 4, Article 2, Section 2, Clause 1, Document 9
The University of Chicago Press
Tucker, St. George. Blackstone's Commentaries: With Notes of Reference to the Constitution and Laws of the Federal Government of the United States and of the Commonwealth of Virginia. 5 vols. Philadelphia, 1803. Reprint. South Hackensack, N.J.: Rothman Reprints, 1969.