United States of America
Practice Relating to Rule 108. Mercenaries
Section A. Definition of mercenaries
The US Air Force Commander’s Handbook (1980) states:
Until recently, there was no generally accepted definition of a “mercenary,” but the term was usually applied to foreigners who took part in an armed conflict on one side or the other, primarily for high pay or hope of booty … The definition of “mercenary” in [the 1977 Additional Protocol I] is so narrow that few persons would fit within it. The United States has signed this Protocol but has not yet ratified it.
In 1987, the Deputy Legal Adviser of the US Department of State affirmed:
We do not favor the provisions of article 47 on mercenaries, which among other things introduce political factors that do not belong in international humanitarian law, and do not consider the provisions of article 47 to be part of current customary law.