g McClellan to action; Wilson in 1918
settled the question of an independent American command on the Western
Front; Truman in 1945 ordered that the bomb be dropped on Hiroshima and
Nagasaki. As against an enemy in the field the President possesses all
the powers which are accorded by International Law to any supreme
commander. "He may invade the hostile country, and subject it to the
sovereignty and authority of the United States."[97] In the absence of
attempts by Congress to limit his power, he may establish and prescribe
the jurisdiction and procedure of military commissions, and of tribunals
in the nature of such commissions, in territory occupied by Armed Forces
of the United States, and his authority to do this sometimes survives
cessation of hostilities.[98] He may employ secret agents to enter the
enemy's lines and obtain information as to its strength, resources, and
movements.[99] He may, at least with the assent of Congress, authorize
intercourse with the enemy.[100] He may also requisition property and
compel services from American citizens and friendly aliens who are
situated within the theatre of military operations when necessity
requires, thereby incurring for the United States the obligation to
render "just compensation."[101] By the same warrant he may bring
hostilities to a conclusion by arranging an armistice, stipulating
conditions which may determine to a great extent the ensuing peace.[102]
He may not, however, effect a permanent acquisition of territory;[103]
though he may govern recently acquired territory until Congress sets up
a more permanent regime.[104] He is the ultimate tribunal for the
enforcement of the rules and regulations which Congress adopts for the
government of the forces, and which are enforced through
courts-martial.[105] Indeed, until 1830, courts-martial were convened
solely on his authority as Commander in Chief.[106] Such rules and
regulations are, moreover, it would seem, subject in wartime to his
amendment at discretion.[107] Similarly, the power of Congress to "make
rules for the government and regulation of the law and naval forces"
(Art. I, Sec. 8, cl. 14) did not prevent President Lincoln from
promulgating in April, 1863 a code of rules to govern the conduct in the
field of the armies of the United States which was prepared at his
instance by a commission headed by Francis Lieber and which later
became the basis of all similar codifications both here and abroad.[108]
O