Bennett on targeted killings

Today, the U.S. position is reflected in the DoD Law of War Manual:

However, the broadest protection is found in Article 51(7) of the 1977 Additional Protocol I. It provides,

The presence or movements of the civilian population or individual civilians shall not be used to render certain points or areas immune from military operations, in particular in attempts to shield military objectives from attacks or to shield, favour or impede military operations. The Parties to the conflict shall not direct the movement of the civilian population or individual civilians in order to attempt to shield military objectives from attacks or to shield military operations.

Thus, the Additional Protocol I rule applies to the use of any civilians to shield military operations. Note that the prohibition addresses only the use of civilians and not civilian objects.

With respect to the U.S. position, the former U.S. Ambassador at Large for War Crimes Issues, David Scheffer, confirmed the status of human shielding as both an IHL violation and a war crime, and offered examples, during a 2000 address to I Corps soldiers at Fort Lewis.

Articles 51 and 58 of Protocol I quite properly articulate the principle that a party on the defensive cannot intentionally use civilian noncombatants or civilian property to shield military targets. In one sense, this is simply a refinement of the protected status that civilians and their property enjoy under the laws of armed conflict. (IHL violation)

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States that abuse the status of protected persons and objects commit war crimes, period.

All this and more is set out here.