The Constitution provides, as has been seen, that Congress shall have the power to provide and to make rules for the government and regulation of the land and naval forces. It is also provided that the President 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 actual service of the United States." 3

2 Art. I, Sec. VIII.

Under these grants of power, Congress has established an army and navy, and by laws, passed from time to time, has provided the rules by which the respective powers and duties of the officers and men constituting this military establishment are to be determined and exercised. Collectively these rules are known as the Military Laws of the United States.4