Related Rule
United States of America
Practice Relating to Rule 8. Definition of Military Objectives
The US Air Force Pamphlet (1976) states:
Insofar as objects are concerned, military objectives are limited to those objects which by their own nature, location, purpose or use make an effective contribution to military action and whose total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 5-3(b)(1).
The US Naval Handbook (1995) states:
Military objectives are combatants and those objects which, by their nature, location, purpose or use, effectively contribute to the enemy’s war-fighting or war-sustaining capability and whose total or partial destruction, capture, or neutralization would constitute a definite military advantage to the attacker under the circumstances at the time of the attack. Military advantage may involve a variety of considerations, including the security of the attacking force. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 8.1.1.
The US Naval Handbook (2007) states:
An object is a valid military objective if by its nature (e.g., combat ships and aircraft), location (e.g., bridge over enemy supply route), use (e.g., school building being used as an enemy headquarters), or purpose (e.g., a civilian airport that is built with a longer than required runway so it can be used for military airlift in time of emergency) it makes an effective contribution to the enemy’s war fighting/war sustaining effort and its total or partial destruction, capture, or neutralization, in the circumstance at the time, offers a definite military advantage. Purpose is related to use, but is concerned with the intended, suspected, or possible future use of an object rather than its immediate and temporary use. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 5.3.1; see also § 8.2.
The Handbook also states: “Military advantage may involve a variety of considerations, including security of the attacking force.” 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.2.
The US Manual for Military Commissions (2010), Part IV, Crimes and Elements, defines the term “military objective”:
The term “military objective” means—
(B) those objects during hostilities—
(i) which, by their nature, location, purpose, or use, effectively contribute to the opposing force’s war-fighting or war-sustaining capability; and
(ii) the total or partial destruction, capture, or neutralization of which would constitute a definite military advantage to the attacker under the circumstances at the time of the attack. 
United States, Manual for Military Commissions, published in implementation of Chapter 47A of Title 10, United States Code, as amended by the Military Commissions Act of 2009, 10 U.S.C, §§ 948a, et seq., 27 April 2010, § 1(a)(1), p. IV-1.
The US Military Commissions Act (2006), passed by Congress following the Supreme Court’s decision in Hamdan v. Rumsfeld in 2006, amends Title 10 of the United States Code as follows:
§ 950v. Crimes triable by military commissions
“(a) DEFINITIONS AND CONSTRUCTION. – In this section:
“(1) MILITARY OBJECTIVE. – The term “military objective” means –
“(A) combatants; and
“(B) those objects during an armed conflict –
“(i) which, by their nature, location, purpose, or use, effectively contribute to the opposing force’s war-fighting or war-sustaining capability; and
“(ii) the total or partial destruction, capture, or neutralization of which would constitute a definite military advantage to the attacker under the circumstances at the time of the attack. 
United States, Military Commissions Act, 2006, Public Law 109-366, Chapter 47A of Title 10 of the United States Code, 17 October 2006, p. 120 Stat. 2625, § 950v(a)(1).
The US Military Commissions Act (2009) amends Chapter 47A of Title 10 of the United States Code as follows:
Ҥ 950p. Definitions; construction of certain offenses; common circumstances
“(a) DEFINITIONS.—In this subchapter:
“(1) The term “military objective” means … those objects during hostilities which, by their nature, location, purpose, or use, effectively contribute to the war-fighting or war-sustaining capability of an opposing force and whose total or partial destruction, capture, or neutralization would constitute a definite military advantage to the attacker under the circumstances at the time of an attack. 
United States, Military Commissions Act, 2009, § 950p(a)(1).
In 1972, the General Counsel of the US Department of Defense stated:
In the application of the laws of war, it is important that there be a general understanding in the world community as to what shall be legitimate military objectives which may be attacked by air bombardment under the limitations imposed by treaty or by customary international law. Attempts to limit the effects of attacks in an unrealistic manner, by definition or otherwise, solely to the essential war making potential of enemy States have not been successful. For example, such attempts as the 1923 Hague Rules of Air Warfare, proposed by an International Commission of Jurists, and the 1956 ICRC Draft Rules for the Limitation of Dangers Incurred by the Civilian Population in Time of War were not accepted by States and therefore do not reflect the laws of war either as customary international law or as adopted by treaty. [The General Counsel then refers to Articles 1 and 2 of the 1907 Hague Convention (IX) and Article 8 of the 1954 Hague Convention as reflecting customary international law.] The test applicable from the customary international law, restated in [Article 8 of] the Hague Cultural Property Convention, is that the war making potential of such facilities to a party to the conflict may outweigh their importance to the civilian economy and deny them immunity from attack. Turning to the deficiencies in the Resolutions of the Institut de Droit International [adopted at its Edinburgh Session in 1969], and with the foregoing in view, it cannot be said that Paragraph 2, which refers to legal restraints that there must be an “immediate” military advantage, reflects the law of armed conflict that has been adopted in the practices of States. 
United States, Letter from J. Fred Buzhardt, General Counsel of the Department of Defense, to Senator Edward Kennedy, Chairman of the Subcommittee on Refugees of the Committee on the Judiciary, 22 September 1972, AJIL, Vol. 67, 1973, p. 123.
In 1987, the Deputy Legal Adviser of the US Department of State stated: “The United States has no great concern over the new definition of ‘military objective’ set forth in Article 52(2) of [the 1977 Additional] Protocol I.” 
United States, Remarks of Michael J. Matheson, Deputy Legal Adviser, US Department of State, The Sixth Annual American Red Cross-Washington College of Law Conference on International Humanitarian Law: A Workshop on Customary International Law and the 1977 Protocols Additional to the 1949 Geneva Conventions, American University Journal of International Law and Policy, Vol. 2, 1987, p. 436.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated:
When objects are used concurrently for civilian and military purposes, they are liable to attack if there is a military advantage to be gained in their attack. (“Military advantage” is not restricted to tactical gains, but is linked to the full context of a war strategy, in this instance, the execution of the Coalition war plan for liberation of Kuwait.) 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Appendix O, The Role of the Law of War, ILM, Vol. 31, 1992, p. 623.
In 1992, in a review of the legality of extended range anti-armour munition, the US Department of the Air Force relied on the definition of military objectives set forth in Article 52(2) of the 1977 Additional Protocol I.  
United States, Department of the Air Force, The Judge Advocate General, Legal Review: Extended Range Antiarmor Munition (ERAM), 16 April 1992, § 7.
The Report on US Practice states:
The opinio juris of the U.S. government recognizes the definition of military objectives in Article 52 of Additional Protocol I as customary law. United States practice gives a broad reading to this definition, and would include areas of land, objects screening other military objectives, and war-supporting economic facilities as military objectives. The foreseeable military advantage from an attack includes increasing the security of the attacking force. In any event, the anticipated military advantage need not be expected to immediately follow the success of the attack, and may be inferred from the whole military operation of which the attack is a part. 
Report on US Practice, 1997, Chapter 1.3.
The US Air Force Pamphlet (1976) considers that “troops in the field are military objectives beyond any dispute”. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 5-3(b)(2).
According to the US Naval Handbook (1995), combatants and troop concentrations are military objectives. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 8.1.1.
The US Naval Handbook (2007) states: “Military objectives are combatants”. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.2.
The Handbook also states: “Proper objects of attack include, but are not limited to, such military objectives as … troop concentrations”. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.2.5.
The US Manual for Military Commissions (2010), Part IV, Crimes and Elements, states that: “The term ‘military objective’ means – (A) combatants”. 
United States, Manual for Military Commissions, published in implementation of Chapter 47A of Title 10, United States Code, as amended by the Military Commissions Act of 2009, 10 U.S.C, §§ 948a, et seq., 27 April 2010, § 1(a)(1), p. IV-1.
The US Military Commissions Act (2009) amends Chapter 47A of Title 10 of the United States Code as follows:
Ҥ 950p. Definitions; construction of certain offenses; common circumstances
“(a) DEFINITIONS.—In this subchapter:
“(1) The term “military objective” means combatants. 
United States, Military Commissions Act, 2009, § 950p(a)(1).
In 1950, the US Secretary of State stated: “The air activity of the United Nations forces in Korea has been, and is, directed solely at military targets of the invader. These targets [include] enemy troop concentrations.” 
United States, Statement by the Secretary of State, Dean Acheson, 6 September 1950, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 140.
In 1991, in a report submitted to the UN Security Council on operations in the Gulf War, the United States stated that it considered the “occupation forces in Kuwait and southern Iraq” as legitimate military targets. It also stated that it had attacked Iraq’s naval forces in the northern Gulf and specified: “These attacks have been on Iraqi units that are engaged in operations against coalition forces.” 
United States, Letter dated 22 January 1991 to the President of the UN Security Council, UN Doc. S/22130, 22 January 1991, p. 1.
In a subsequent report, the United States stated that the Republican Guard remained a “high priority” target. 
United States, Letter dated 30 January 1991 to the President of the UN Security Council, UN Doc. S/22173, 30 January 1991, p. 1.
In another such report, the United States reiterated that it considered “the Republican Guard and other ground troops in the Kuwaiti theater of operations” as a legitimate target of attack. 
United States, Letter dated 8 February 1991 to the President of the UN Security Council, UN Doc. S/22216, 13 February 1991, p. 1
In 1991, during a news briefing concerning the Gulf War, the US Secretary of Defense stated that the “mainstay of Saddam’s command forces, the Republican Guard units located near the Iraqi/Kuwaiti border” were considered military targets and had been attacked. 
United States, News Briefing by the US Secretary of Defense and the Chairman of the Joint Chiefs of Staff, Washington, 23 January 1991, annexed to Letter dated 25 January 1991 to the President of the UN Security Council, UN Doc. S/22168, 29 January 1991, p. 3.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated that Iraq’s air forces, naval forces and army units, including the Republican Guard, had been included among the 12 target sets for the coalition’s attacks. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Chapter VI, The Air Campaign, pp. 96–98.
The US Air Force Pamphlet (1976) considers that “an adversary’s military encampments … are military objectives beyond any dispute”. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 5-3(b).
According to the US Naval Handbook (1995), proper targets for naval attack include such military objectives as naval and military bases ashore; warship construction and repair facilities; military depots and warehouses; petroleum/oils/lubricants (POL) storage areas; and buildings and facilities that provide administrative and personnel support for military and naval operations, such as barracks, headquarters buildings, mess halls and training areas. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 8.1.1.
The US Naval Handbook (2007) states:
Proper objects of attack include, but are not limited to, such military objectives as … naval and military bases ashore, warship construction and repair facilities, military depots and warehouses, petroleum/oils/lubricants storage areas … buildings and facilities that provide administrative and personnel support for military and naval operations such as barracks, … headquarters buildings, mess halls, and training areas.  
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.2.5.
In 1950, the US Secretary of State stated: “The air activity of the United Nations forces in Korea has been, and is, directed solely at military targets of the invader. These targets [include] … supply dumps”. 
United States, Statement by the Secretary of State, Dean Acheson, 6 September 1950, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 140.
In 1966, in the context of the Vietnam War, the US Department of Defense stated: “Military targets include but are not limited to … POL [petroleum/oils/lubricants] facilities, barracks and supply depots. In the specific case of Nam Dinh and Phu Li, targets have been limited to … POL dumps”. 
United States, Department of Defense, Statement on targeting policy in Vietnam, 26 December 1966, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 427.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated that Iraq’s military storage and production sites had been included among the 12 target sets for the coalition’s attacks. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Chapter VI, The Air Campaign, p. 98.
The US Air Force Pamphlet (1976) considers that an adversary’s “armament, such as military aircraft, tanks, antiaircraft emplacements … are military objectives beyond any dispute”. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 5-3(b)(2).
The US Naval Handbook (1995) specifies that “proper targets for naval attack include such military objectives as enemy warships and military aircraft, naval and military auxiliaries, … military vehicles, armor, artillery, ammunition stores”. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 8.1.1.
The US Naval Handbook (2007) states: “Proper objects of attack include, but are not limited to, such military objectives as enemy warships and military aircraft, naval and military auxiliaries … military vehicles, armor, artillery, [and] ammunition stores”. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.2.5; see also § 8.6.1.
In 1966, in the context of the Vietnam War, the US Department of Defense stated that military targets “also include those anti-aircraft and SAM sites which endanger the lives of American pilots … In the specific case of Nam Dinh and Phu Li, targets have been limited to … air defense sites.” 
United States, Department of Defense, Statement on targeting policy in Vietnam, 26 December 1966, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 427.
In 1991, in a report submitted to the UN Security Council on operations in the Gulf War, the United States stated that military targets included “Iraqi biological and chemical warfare facilities, mobile and fixed surface-to-surface missile sites … and the air defense networks that protect these facilities” as well as “Iraqi artillery positions”. 
United States, Letter dated 22 January 1991 to the President of the UN Security Council, UN Doc. S/22130, 22 January 1991, p. 1.
In another such report, the United States stated that “surface-to-surface missile capabilities remain as high priority targets”. 
United States, Letter dated 30 January 1991 to the President of the UN Security Council, UN Doc. S/22173, 30 January 1991, p. 1.
In the same report, the United States stated that “the naval forces of the United States have also engaged Iraqi patrol and mine-laying craft in the Northern Arabian Gulf”. 
United States, Letter dated 30 January 1991 to the President of the UN Security Council, UN Doc. S/22173, 30 January 1991, p. 1.
In a subsequent report, the United States stated that allied attacks had targeted “air defence, combat aircraft in the air and on the ground, nuclear, biological and chemical storage facilities”, as well as “air defence radars and missiles in Kuwait” and “surface-to-surface missile capabilities”. 
United States, Letter dated 8 February 1991 to the President of the UN Security Council, UN Doc. S/22216, 13 February 1991, p. 1.
In the same report, the United States reiterated that “the naval forces of the United States and the allied coalition have continued to engage Iraqi patrol and mine-laying craft in the Northern Arabian Gulf”. 
United States, Letter dated 8 February 1991 to the President of the UN Security Council, UN Doc. S/22216, 13 February 1991, p. 2.
In 1991, during a news briefing concerning the Gulf War, the US Secretary of Defense stated that “air defence units and radars”, “SCUD missile launchers” and “the factories where Iraq has produced chemical and biological weapons, and until recently, continued working on nuclear weapons” were considered military targets and had been attacked. 
United States, News Briefing by the US Secretary of Defense and the Chairman of the Joint Chiefs of Staff, Washington, 23 January 1991, annexed to Letter dated 25 January 1991 to the President of the UN Security Council, UN Doc. S/22168, 29 January 1991, p. 3.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated that Iraq’s strategic integrated air defense system, its nuclear, biological and chemical weapons research, production and storage facilities and its Scud missiles, launchers, and production and storage facilities had been included among the 12 target sets for the coalition’s attacks. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Chapter VI, The Air Campaign, pp. 96 and 98.
The US Air Force Pamphlet (1976) states:
Controversy exists over whether, and the circumstances under which, other objects, such as civilian transportation and communications systems, dams and dikes can be classified properly as military objectives … A key factor in classification of objects as military objectives is whether they make an effective contribution to an adversary’s military action so that their capture, destruction or neutralization offers a definite military advantage in the circumstances ruling at the time. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 5-3(b)(2).
The US Naval Handbook (1995) considers communications and command and control facilities, as well as “lines of communication and other objects used to conduct or support military operations”, as proper targets for naval attack. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 8.1.1.
The US Naval Handbook (2007) states:
Proper objects of attack include, but are not limited to, such military objectives as … lines of communication and other objects used to conduct or support military operations … [and] communications and command and control facilities. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.2.5.
During the Korean War, the United States reportedly attacked communication centres in North Korea. 
Robert F. Futrell, The United States Air Force in Korea 1950–1953, Office of Air Force History, United States Air Force, Washington, D.C., Revised edition, 1983, p. 516.
In 1950, the US Secretary of State stated: “The air activity of the United Nations forces in Korea has been, and is, directed solely at military targets of the invader. These targets [include] … communications lines.” 
United States, Statement by Dean Acheson, Secretary of State, 6 September 1950, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 140.
In 1991, in reports submitted to the UN Security Council on operations in the Gulf War, the United States included command and control centres among Iraq’s military targets. 
United States, Letter dated 22 January 1991 to the President of the UN Security Council, UN Doc. S/22130, 22 January 1991, p. 1; Letter dated 8 February 1991 to the President of the UN Security Council, UN Doc. S/22216, 13 February 1991, p. 1.
In 1991, during a news briefing concerning the Gulf War, the US Secretary of Defense stated that “command and control [and] communications facilities” were considered military targets and had been attacked. 
United States, News Briefing by the US Secretary of Defense and the Chairman of the Joint Chiefs of Staff, Washington, 23 January 1991, annexed to Letter dated 25 January 1991 to the President of the UN Security Council, UN Doc. S/22168, 29 January 1991, p. 3.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated that Iraq’s leadership command facilities, its telecommunications and command, control and communication nodes had been included among the 12 target sets for the coalition’s attacks. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Chapter VI, The Air Campaign, pp. 95–96.
The report specified that:
To challenge [Saddam Hussein’s] C3 [command, control and communication], the Coalition bombed microwave relay towers, telephone exchanges, switching rooms, fiber optic nodes, and bridges that carried coaxial communications cables … More than half of Iraq’s military landline communications passed through major switching facilities in Baghdad. Civil TV and radio facilities could be used easily for C3 backup for military purposes. The Saddam Hussein regime also controlled TV and radio and used them as the principal media for Iraqi propaganda. Thus, these installations were also struck. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Chapter VI, The Air Campaign, p. 96; see also James P. Coyne, Plan of Attack, Air Force Magazine, April 1992, pp. 40–42.
In the same report, the Department of Defense stated: “Microwave towers for everyday, peacetime civilian communications can constitute a vital part of a military command and control (C2) system … Attack of all segments of the Iraqi communications system was essential to destruction of Iraqi military C2.” 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Appendix O, The Role of the Law of War, ILM, Vol. 31, 1992, p. 623.
The US Air Force Pamphlet (1976) states:
Controversy exists over whether, and the circumstances under which, other objects, such as civilian transportation and communications systems, dams and dikes can be classified properly as military objectives … A key factor in classification of objects as military objectives is whether they make an effective contribution to an adversary’s military action so that their capture, destruction or neutralization offers a definite military advantage in the circumstances ruling at the time. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 5-3(b)(2).
The US Naval Handbook (1995) lists airfields, bridges, railyards, docks, port facilities, harbours and embarkation points as military objectives. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 8.1.1.
The US Naval Handbook (2007) states: “Proper objects of attack include, but are not limited to, such military objectives as … embarkation points … docks, port facilities, harbors, bridges, [and] airfields”. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.2.5.
During the Korean War, the US Joint Chiefs of Staff informed General MacArthur that mass air operations against industrial targets in North Korea were “highly desirable”. The Joint Chiefs of Staff accordingly designated, inter alia, the following targets: the railway yards and shops at Pyongyang, the railway yards and shops at Wonsan, the railway yards and shops and the harbour facilities at Chongjin, the railway yards at Chinnampo, the railway yards and shops and the docks and storage areas at Songjin, the railway yards at Hamhung and the railway yards at Haeju. 
United States, Letter dated 13 February 1991 to the President of the UN Security Council, UN Doc. S/22218, 13 February 1991, p. 1.
In 1966, in the context of the Vietnam War, the US Secretary of Defense stated:
We are directing the aircraft against military targets, only military targets, and those particularly associated with the lines of communication between North Vietnam and South Vietnam over which they are sending the men and equipment which are the foundation of the Viet Cong effort to subvert the Government of South Vietnam. 
United States, Secretary of Defense, Statement on targeting policy in Vietnam, 2 February 1966, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 427.
In 1966, in the context of the Vietnam War, the US Department of Defense stated:
U.S. policy is to target military targets only, particularly those which have a direct impact on the movement of men and supplies into South Vietnam. These targets include but are not limited to roads, railroads, bridges [and] road junctions … In the specific case of Nam Dinh and Phu Li, targets have been limited to railroad and highway bridges, railroad yards … 
United States, Department of Defense, Statement on targeting policy in Vietnam, 26 December 1966, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 427.
In 1991, in a report submitted to the UN Security Council on operations in the Gulf War, the United States included “supply lines” among Iraq’s military targets. 
United States, Letter dated 22 January 1991 to the President of the UN Security Council, UN Doc. S/22130, 22 January 1991, p. 1.
In another such report, the United States stated that “the supply lines leading from Iraq into Kuwait” were to be targeted by coalition forces. 
United States, Letter dated 8 February 1991 to the President of the UN Security Council, UN Doc. S/22216, 13 February 1991, p. 1.
In 1991, during a news briefing concerning the Gulf War, the US Secretary of Defense stated that “airfields” were considered military targets and had been attacked. 
United States, News Briefing by the US Secretary of Defense and the Chairman of the Joint Chiefs of Staff, Washington, 23 January 1991, annexed to Letter dated 25 January 1991 to the President of the UN Security Council, UN Doc. S/22168, 29 January 1991, p. 3.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated that Iraq’s airfields, its port facilities, and its railroads and bridges had been included among the 12 target sets for the coalition’s attacks. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Chapter VI, The Air Campaign, pp. 96–98.
In the same report, the US Department of Defense stated:
A bridge or highway vital to daily commuter and business traffic can be equally crucial to military traffic, or support for a nation’s war effort. Railroads, airports, seaports and the interstate highway system in the United States have been funded by the Congress in part because of US national security concerns, for example; each proved invaluable to the movement of US military units to various ports for deployment to Southwest Asia (SWA) for Operations Desert Shield and Desert Storm. Destruction of a bridge, airport, or port facility, or interdiction of a highway can be equally important in impeding an enemy’s war effort. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Appendix O, The Role of the Law of War, ILM, Vol. 31, 1992, p. 623; see also James P. Coyne, Plan of Attack, Air Force Magazine, April 1992, pp. 40–42.
The US Naval Handbook (1995) states:
Proper economic targets for naval attack include enemy lines of communication, rail yards, bridges, rolling stock, barges, lighters, industrial installations producing war-fighting products, and power generation plants. Economic targets of the enemy that indirectly but effectively support and sustain the enemy’s war-fighting capability may also be attacked. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 8.1.1.
The US Naval Handbook (2007) states:
Proper objects of attack also include enemy lines of communication, rail yards, bridges, rolling stock, barges, lighters, industrial installations producing war-fighting products, and power generation plants. Economic objects of the enemy that indirectly but effectively support and sustain the enemy’s war-fighting capability may also be attacked. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.2.5.
During the Korean War, the US Joint Chiefs of Staff informed General MacArthur that mass air operations against industrial targets in North Korea were “highly desirable”. The Joint Chiefs of Staff accordingly designated, inter alia, the following targets: the two munitions plants at Pyongyang, the three chemical plants at Hungnam, the oil refinery at Wonsan, the naval oil-storage tank farm at Rashin, the “Tong Iron Foundry” and the “Sam Yong Industrial Factory” at Chinnampo. 
Robert F. Futrell, The United States Air Force in Korea 1950–1953, Office of Air Force History, US Air Force, Washington, D.C., Revised edition, 1983, pp. 186–187; see also pp. 517–518 (discussing the North Korean metals and mining business as a target category).
In 1950, the US Secretary of State stated: “The air activity of the United Nations forces in Korea has been, and is, directed solely at military targets of the invader. These targets [include] … war plants.” 
United States, Statement by the Secretary of State, Dean Acheson, 6 September 1950, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 140.
In 1966, in reply to an inquiry from a member of the House of Representatives asking for a restatement of US policy on targeting in North Vietnam, a US Deputy Assistant Secretary of Defense wrote: “The United States has not targeted such installations as textile plants, fruit-canning plants, silk factories and thread cooperatives.” 
United States, Letter from Deputy Assistant Secretary of Defense Goulding to US Representative Ogden Reid from New York, 30 December 1966, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 428.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated that Iraq’s electricity production facilities, its oil refining and distribution facilities and its military production sites had been included among the 12 target sets for the coalition’s attacks. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Chapter VI, The Air Campaign, pp. 96–98.
In 1993, in its report to Congress on the protection of natural and cultural resources during times of war, the US Department of Defense stated:
Natural resources that may be of value to an enemy in his war effort are legitimate targets. The 1943 air raids on the Ploesti oil fields in Romania, and the Combined Bomber Offensive campaign against Nazi oil, were critical to allied defeat of Germany in World War II, for example … During Desert Storm, Coalition planners targeted Iraq’s ability to produce refined oil products (such as gasoline) that had immediate military use, but eschewed attack on its long-term crude oil production capability. 
United States, Department of Defense, Report to Congress on International Policies and Procedures Regarding the Protection of Natural and Cultural Resources During Times of War, 19 January 1993, p. 204.
The Report on US Practice states:
The opinio juris of the U.S. government recognizes the definition of military objectives in Article 52 of Additional Protocol I as customary law. United States practice gives a broad reading to this definition, and would include … war-supporting economic facilities as military objectives. 
Report on US Practice, 1997, Chapter 1.3.
The US Naval Handbook (1995) states: “Proper naval targets also include geographic targets, such as a mountain pass.” 
United States, The Commander’s Handbook on the Law of Naval Operations , NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 8.1.1.
The US Naval Handbook (2007) states: “Proper objects of attack include, but are not limited to, such military objectives as … geographic features, such as a mountain pass”. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.2.5.
At the CDDH, the United States expressed its understanding that:
A specific area of land may be a military objective if, because of its location or other reasons specified in Article 47 [now Article 52 of the 1977 Additional Protocol I], its total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage. 
United States, Statement at the CDDH, Official Records, Vol. VI, CDDH/SR.41, 26 May 1977, p. 204.
In 1992, in a review of the legality of extended range anti-armour munition, the US Department of the Air Force stated:
An area of land can be a military objective if by its nature, location, purpose or use it makes an effective contribution to military action and its total or partial destruction, denial, capture or neutralization offers a definite military advantage, in the circumstances ruling at the time. Most areas which would be mined in war would meet this definition. 
United States, Department of the Air Force, The Judge Advocate General, Legal Review: Extended Range Antiarmor Munition (ERAM), 16 April 1992, § 7.
The Report on US Practice states:
The opinio juris of the U.S. government recognizes the definition of military objectives in Article 52 of Additional Protocol I as customary law. United States practice gives a broad reading to this definition, and would include areas of land … as military objectives. 
Report on US Practice, 1997, Chapter 1.3.
Upon acceptance of the 1996 Amended Protocol II to the 1980 Convention on Certain Conventional Weapons, the United States stated:
The United States understands that an area of land itself can be a legitimate military objective for the purpose of the use of landmines, if its neutralization or denial, in the circumstances applicable at the time, offers a military advantage. 
United States, Declaration made upon acceptance of the 1996 Amended Protocol II to the 1980 Convention on Certain Conventional Weapons, 24 May 1999, § 4.
The US Naval Handbook (1995) states:
Deliberate use of noncombatants to shield military objectives from enemy attack is prohibited. Although the principle of proportionality underlying the concept of collateral damage and incidental injury continues to apply in such cases, the presence of non-combatants within or adjacent to a legitimate target does not preclude attack of it … Unlike military personnel (other than those in a specially protected status such as medical personnel and the sick and wounded) who are always subject to attack whether on duty or in a leave capacity, civilians, as a class, are not to be the object of attack. However, civilians that are engaged in direct support of the enemy’s war-fighting or war-sustaining effort are at risk of incidental injury from attack on such activities. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), §§ 11.2 and 11.3.
The US Naval Handbook (2007) states:
Although the principle of proportionality underlying the concept of collateral damage continues to apply in such cases, the presence of civilians within or adjacent to a legitimate military objective does not preclude attack of it. Such military objectives may be lawfully targeted and destroyed as needed for mission accomplishment. In such cases, responsibility for the injury and/or death of such civilians, if any, falls on the belligerent so employing them.
The presence of civilian workers, such as technical representatives aboard a warship or employees in a munitions factory, in or on a military objective, does not alter the status of the military objective. These civilians may be excluded from the proportionality analysis.
Civilians who voluntarily place themselves in or on a military objective as “human shields” in order to deter a lawful attack do not alter the status of the military objective. While the law of armed conflict is not fully developed in such cases, such persons may also be considered to be taking a direct part in hostilities or contributing directly to the enemy’s warfighting/war-sustaining capability, and may be excluded from the proportionality analysis. Attacks under such circumstances likely raise political, strategic, and operational issues that commanders should identify and consider when making targeting decisions. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.3.2.
In 1989, a US memorandum of law concerning the prohibition of assassination stated:
Civilians who work within a military objective are at risk from attack during the times in which they are present within that objective, whether their injury or death is incidental to the attack of that military objective or results from their direct attack … The substitution of a civilian in a position or billet that normally would be occupied by a member of the military will not make that position immune from attack. 
United States, Department of the Army, Office of the Judge Advocate General, Memorandum of Law: Executive Order 12333 and Assassination, 2 November 1989, The Army Lawyer, Pamphlet 27-50-204, December 1989.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated:
Civilians using those bridges or near other targets at the time of their attack were at risk of injury incidental to the legitimate attack of those targets … The presence of civilians will not render a target immune from attack; legitimate targets may be attacked wherever located (outside neutral territory and waters). 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Appendix O, The Role of the Law of War, ILM, Vol. 31, 1992, pp. 624 and 625.