DEPARTMENTOFDEFENSE LAW OFWARMANUAL JUNE2015

into “hostilities.” 75 Other statutes may require a determination that conduct has occurred
“[w]hen the United States is at war” or during “time of war.” 76
Under international law, “war,” “hostilities,” and “armed conflict” may also be
interpreted with different purposes in mind. 77 A state of “war” can affect what duties States that
are not participating in the conflict have under the law of neutrality. 78 A state of “war” can affect
whether peacetime treaties between two States continue to apply. Most importantly for the
purposes of this manual, the terms “war” and “armed conflict” are used to describe when jus in
bello rules apply. 79
1.6 LAW OF WAR DISTINGUISHED FROM CERTAIN TOPICS
The law of war may be distinguished from the following topics: (1) operational law; (2)
arms control; (3) human rights treaties; (4) the Just War Tradition; (5) rules of engagement; and
(6) the Code of Conduct for U.S. Armed Forces.
1.6.1 Operational Law. The law of war is an important part of, but not the entirety of,
operational law. Operational law consists of that body of domestic, foreign, and international
law that specifically pertains to the activities of military forces across the entire conflict
spectrum. Operational law includes diverse legal disciplines, such as military justice,
administrative and civil law, legal assistance, claims, procurement law, national security law,
fiscal law, and the law of war. 80
75 See 50 U.S.C. § 1543(a)(1) (“In the absence of a declaration of war, in any case in which United States Armed
Forces are introduced— (1) into hostilities or into situations where imminent involvement in hostilities is clearly
indicated by the circumstances; … the President shall submit within 48 hours to the Speaker of the House of
Representatives and to the President pro tempore of the Senate a report, in writing, setting forth … .”).
76 See, e.g., 10 U.S.C. § 843(f) (“When the United States is at war, the running of any statute of limitations
applicable to [certain offenses]… is suspended until three years after the termination of hostilities as proclaimed by
the President or by a joint resolution of Congress.”); 10 U.S.C. § 906 (“Any person who in time of war is found
lurking as a spy or acting as a spy in or about any place, vessel, or aircraft, within the control or jurisdiction of any
of the armed forces, or in or about any shipyard, any manufacturing or industrial plant, or any other place or
institution engaged in work in aid of the prosecution of the war by the United States, or elsewhere, shall be tried by a
general court-martial or by a military commission and on conviction shall be punished by death. This section does
not apply to a military commission established under chapter 47A of this title.”).
77 JULIUS STONE, LEGAL CONTROLS OF INTERNATIONAL CONFLICT 312 (1954) (“[T]he question ‘War or No War?’
may have to be answered differently according to the purposes for which an answer is sought. One answer, for
example, may be indicated for the purposes of the rules for the mitigation of suffering; another for those governing
war supplies to belligerents from neutral governments, or governing blockade or contraband.”).
78 Refer to § 15.2.1 (Armed Conflict and the Application of the Law of Neutrality).
79 Refer to § 3.4 (When Jus in Bello Rules Apply).
80 THE JUDGE ADVOCATE GENERAL’S SCHOOL, U.S. ARMY, OPERATIONAL LAW HANDBOOK JA 422 1-1 (1997)
(“[Operational law is] [t]hat body of domestic, foreign, and international law that impacts specifically upon the
activities of U.S. Forces across the entire operational spectrum. Operational law is the essence of the military legal
practice. It is a collection of diverse legal and military skills, focused on military operations. It includes military
justice, administrative and civil law, legal assistance, claims, procurement law, environmental law, national security
law, fiscal law, international law, host nations law, and the law of war. In short, operational law is a unique blend of
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