What is the status of civilians who are important to the war effort?

Question

Suppose two countries are involved in an international armed conflict, say an officially declared war. For clarity, suppose the front line remains the internationally recognised border. On their own side of this border one person, say a sniper, sees a person on the other side whose profession is clear. They target that person and kill them.

My understanding is that the legality of this act depends on if the person is "taking no active part in the hostilities". What if the person was not a member of the armed forces, but was important to the immediate or overall war effort? Examples that spring to mind are:

• A senior decision maker, perhaps the head of state, perhaps the secretary for defence who is a noted strategic genius
• An armed member of a private military company, such as Wagner Group or Triple Canopy.
• Civilian contractors repairing transport, power or communication infrastructure important to the immediate active conflict
• Civilian scientists working on advancing the opponents weapons capacities in the medium to long term
• Civilians working in the military logistics supply chain, say train or lorry drivers transporting military equipment

Distinction from Other Questions

This one looks similar, but it is focused on if soldiers become no longer valid targets when they are not actively soldering, rather than if civilians become valid targets by virtue of their role.

This describes the Geneva Convention Relative to the Protection of Civilian Persons in Time of War and it seems it comes down to "taking no active part in the hostilities", but it is not clear if my examples would count as that.

Answer 1

They are non-combatants and illegitimate as targets

The Geneva Convention is not complicated on this:

According to the definitions provided by the Geneva Conventions and their first 1977 Additional Protocols, combatants are members of national armed forces or organized groups placed under the effective control of those forces. It is this authorization to use force that distinguishes combatants from civilians.

If you are not a combatant, you are a civilian - both are protected by the laws of war in different ways. Some countries, led by the USA starting in the early 21st century have asserted the existence of a third category, unlawful combatant and are not protected by the laws of war, however, this has no general support in international law.

For your examples:

• A senior decision maker

  • if they are a civilian, like the President of the United States, they are a non-combatant.
  • If they are honours members of the military, like the King of Canada, they are combatants but not valid targets because they never engage in hostilities
  • if they are actually members of the armed forces, like some military dictators, they are combatants and valid targets

• An armed member of a private military company - combatant

• Civilian contractors … - non-combatant

• Civilian scientists … - non-combatant

• Civilians working in the military logistics supply chain - non-combatant