United States of America
Practice Relating to Rule 14. Proportionality in Attack
Section B. Determination of the anticipated military advantage
The US Naval Handbook (1995) states that the term military advantage “refers to the advantage anticipated from the military operation of which the attack is a part, taken as a whole, and not from isolated or particular parts of that operation”.
The US Naval Handbook (2007) states: “Military advantage may involve a variety of considerations, including the security of the attacking force.”
At the CDDH, the United States stated that in its view the expression “military advantage anticipated” was intended to refer to “the advantage anticipated from the attack considered as a whole and not only from isolated or particular parts of the attack”.
In 1991, in reaction to an ICRC memorandum on the applicability of IHL in the Gulf region, the US Department of the Army pointed out:
The concept of “incidental loss of life excessive in relation to the military advantage anticipated” generally is measured against an overall campaign. While it is difficult to weigh the possibility of collateral civilian casualties on a target-by-target basis, minimization of collateral civilian casualties is a continuing responsibility at all levels of the targeting process.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated that the balancing of collateral damage against military gain “may be done on a target-by-target basis, as frequently was the case during Operation Desert Storm, but also may be weighed in overall terms against campaign objectives”.
The Report on US Practice states:
United States practice recognizes the principle of proportionality as part of the customary law of non-nuclear war. In applying this principle, it is necessary to consider military advantage not only on an immediate or target-by-target basis, but also in light of the military objectives of an entire campaign or operation.