Law of War Handbook 2005

4. Reaching fnendly lines immunizes spy for past espionage activities.
   Therefore, upon later capture as a lawful combatant, past spy cannot be tried
   for past espionage.

D. Belligerent or wartime reprisals. FM 27-10, para 497. An otherwise illegal act
done in response to a prior illegal act by the enemy. The purpose of a reprisal is
to get the enemy to adhere to the law of war.

1. Reprisals are authorized if the following requirements are met:

a.  it's timely;

b. it's responsive to enemy's act that violated the law of war;

c.  it follows an unsatisfied demand to cease and desist; and

d.  it is proportionate.

2. Prisoners of war and persons "in your control" cannot be objects of reprisals.
   Protocol I prohibits reprisals against numerous targets such as the entire
   civilian population, civilian property, cultural property, objects indispensable
   to the survival of the civilian population (food, livestock, drinking water), the
   natural environment, installations containing dangerous forces (dams, dikes,
   nuclear power plants) (GP I, arts. 5 1-56). The U.S. specifically objects to
   Article 5 l(6) as not reflective of customary international law.


3. US policy is that a reprisal may be ordered only at the highest levels
   (President).