United States of America
Practice Relating to Rule 14. Proportionality in Attack
Section C. Information required for judging proportionality in attack
The US Naval Handbook (1995) states: “The commander must determine whether incidental injuries and collateral damage would be excessive, on the basis of an honest and reasonable estimate of the facts available to him.”
The US Naval Handbook (2007) states that “the commander must determine whether the anticipated incidental injuries and collateral damage would be excessive, on the basis of an honest and reasonable estimate of the facts available to him”.
At the CDDH, the United States stated:
Commanders and others responsible for planning, deciding upon or executing attacks necessarily have to reach decisions on the basis of their assessment of the information from all sources which is available to them at the relevant time.