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Towards a definition of Lethal Autonomous Weapons
By Guillaume Fournier, December 2016
Unmanned combat vehicles have been used by militaries from around the world to lessen
the human cost of war and to gain military advantage, for thousands of years. In ancient Greece,
Thucydides recorded the use of unmanned fire ships by the defenders of Syracuse to defeat the
Athenian fleet. The use of such unmanned ships continued until the 19th
century. The first real
advances in unmanned vehicles started with Nikola Tesla who in 1898 demonstrated a radio-
controlled motorboat to a government representative. The two World Wars (the German Goliath
tracked mine or the Soviet TT-26 Teletank) and the Cold War saw an increase in the development
and the use of unmanned weapons.
Together with the rapid evolution of artificial intelligence, robotics, and of technology in a
number of areas generally, the last decade has seen significant developments in a variety of
unmanned combat vehicles; Unmanned combat aerial vehicles (UCAV), unmanned ground
vehicles (UGV) and Unmanned surface vehicles (USV) have been developed by the United States,
China, Russia, Israel, France and the UK. UCAVs, also called drones (the MQ-9 Reaper, the MQ-
1 Predator or the X-45 for the US, the Elbit Hermes 450 for Israel, the Sperwer or the Thales
Watchkeeper WK450 for France, or and the Mikoyan Skat for Russia). UGVs (the Gladiator
Tactical Unmanned Ground Vehicle, XM1219 Armed Robotic Vehicle or Foster-Miller TALON
SWORDS for the US Army). These vehicles have different functions ranging from
reconnaissance, to combat or defense and have already been used in many of the current ongoing
conflicts (Iraq, Afghanistan, Pakistan, Yemen, and Somalia).
But what constitutes an Unmanned Combat Vehicle, and how such vehicles can be used,
still is the subject of legal debate. Most of the current weapons systems still rely on the supervision
of human operators for finding their way, targeting and shooting. They are not therefore entirely
considered as autonomous. This is about to change with new ground, air and underwater weapons
currently being developed by militaries around the world and that would no longer be just
unmanned under human supervision, but would have some increasing degree of autonomy from
human operators for their mission. They would constitute LAWS: Lethal Autonomous Weapons
Systems.
Some militaries already own weapons systems that possess some degree of autonomy such
as various automatic defensive weapons, or “fire and forget” missiles which only require that their
human operator identify the target and that then proceed on their own. The United States has the
Aegis Combat System and Phalanx Weapons System at sea and the C-RAM and Patriot missile
system on land. Israel has its air defense system “Iron Dome”. These latest weapons are based on
land or on ships and can target and attack incoming threats on their own. Nevertheless, they are
still mostly automatic: they are preprogrammed and only function within the parameters given to
them. Human supervisors can stop them if necessary. They can only attack a limited type of targets
and will not learn by themselves new categories of objects to attack.
So far, and despite holding various meetings on the subject, international instances have
been unable to agree on what should constitute the distinction between automatic and autonomous

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and on the degree of this autonomy. Automatic versus autonomous weapons are distinguished by
the amount of human supervision required – or not – for their operation. Various definitions have
emerged that seek to create categories by degree of independence from human supervision.
Human-in-the-Loop Weapons can select targets and deliver force only with a human command;
Human-on-the-Loop Weapons can select targets and deliver force under the oversight of a human
operator who has the power to override their actions; and Human-out-of-the-Loop Weapons can
select targets and fire without any human intervention1
. Automatic weapons are under the constant
supervision and control of a human operator and are incapable of learning new information or of
changing their goals or targets on their own. Today, the final decision to take, or at least to initiate
or program lethal action still relies to a great extent on a human operator. And as long as such
weapons are programmed to function within predetermined sets of parameters, they cannot be
viewed as fully autonomous. Fully autonomous LAWS on the contrary would be able to choose a
valid target, to shoot and to change or stop an attack on their own, all the while learning and
evolving. This opens an entirely new set of legal, not to mention practical and reliability, issues.
Since 2013, three meetings of legal experts under the auspices of the Convention on Certain
Conventional Weapons (CCW) have failed to produce any internationally accepted definition of
what is an autonomous weapon. The main reason for this failure has been the definition of what
constitutes autonomy itself, and in what part of a weapon’s activity cycle it is applied. The ICRC
which is the leading organization on International Humanitarian Law issues has proposed to define
autonomous weapon systems as “any system that is capable of targeting and initiating the use of
potentially lethal force without direct human supervision and direct human involvement in lethal
decision-making”2
.
A few States (Cuba, Ecuador, Egypt, the Holy See, and Pakistan) a coalition of NGOs such
as the Campaign to Stop Killer Robots3
(52 NGOs from 24 countries) and various scientists4
have
called for a preemptive ban on fully LAWS. Currently no State has talked about developing and
launching fully autonomous weapons that would operate without any kind human supervision, and
many states have affirmed the principle of human control over these weapons, at least at some
level. But that level of human control and the form that it should take, vary greatly from one state
to the other. The United Kingdom5
and France6
consider that autonomous systems should be
defined as ones that operate with a total absence of human supervision or control, and no link
(communication or control) with the military chain of command. France considers as a result that
autonomous weapons that operate without human supervision would go against the necessity for
the armed forces of maintaining command and control7
. The UK has also said that all their weapons
1
https://www.hrw.org/report/2012/11/19/losing-humanity/case-against-killer-robots
2
https://www.icrc.org/eng/assets/files/review/2012/irrc-886-asaro.pdf
3
http://www.stopkillerrobots.org/
4
http://futureoflife.org/open-letter-autonomous-weapons/
5
http://www.reachingcriticalwill.org/images/documents/Disarmament-fora/ccw/2016/meeting-experts-
laws/statements/11April_UnitedKingdom.pdf
6
http://www.unog.ch/80256EDD006B8954/(httpAssets)/5FD844883B46FEACC1257F8F00401FF6/$file/2016_LA
WSMX_CountryPaper_France+CharacterizationofaLAWS.pdf
7
http://www.reachingcriticalwill.org/images/documents/Disarmament-fora/ccw/2016/meeting-experts-
laws/statements/12April_France.pdf

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will always be under human control8
. Other States such as Switzerland have put forward a less
restrictive definition of “weapons systems that are capable of carrying out tasks governed by IHL
in partial or full replacement of a human in the use of force, notably in the targeting cycle”9
. The
majority of States and NGOs have agreed so far on the necessity of some kind of human control
over LAWS. An increasing number of States have been using the term “Meaningful Human
Control”. Other States have been using terms such as “appropriate” or “effective” level of human
control. The United States talks for example in the U.S. Department of Defense Directive 3000.09,
Autonomy in Weapon, of “appropriate levels of human judgment”10
. And some important states
like Russia and China still have to even provide any definition of autonomous weapons. The
problem is that as a result of all this, there is currently no definition of what these vague terms
mean and what they imply concerning the degree of human supervision, in particular on initiating,
stopping or canceling any attack emanating from these weapons.
Fully autonomous weapons that would operate without any kind of human control or
supervision may also appear to be in contradiction with military advantage: military commanders
generally want to be able to decide what, whom and where they are targeting, in order to engage
specific targets that will bring the military advantage they want to gain from the attack. Their
development and deployment may therefore be seen as still far away. But LAWS are going to
continue evolving as artificial intelligence and technology continue to evolve, and as armed forces
see them as a means of reducing troop deployment and exposure, and of providing faster response
time and potential military superiority. They will have increasing degrees of autonomy, and they
will bring with them, beyond the legal aspects, ethical and practical issues as well, which will have
their own legal repercussions. Should man delegate to machines the ability and the will to kill other
human beings? Would such weapons be able to respect the rules of International Humanitarian
Law such as proportionality, distinction and humanity? Humans still remain best suited to apply
judgment on such matters. What would be the consequences of any malfunctioning or hacking of
such machines? Could they turn against their own troops, or against civilian populations? Who
would bear responsibility? Delegating life and death decisions to machines, even ones with
artificial intelligence, remains a troubling and dangerous notion.
Fully autonomous weapons that would operate without any human supervision seem to be
out of the question so far, but the absence of international definitions leaves significant latitude for
too many countries to continue developing weapons with more and more autonomy in various
stages of their operation. It is for this very reason that clearer definitions are needed now, that will
in turn allow for the creation of safer international regulations on LAWS.
8
http://www.reachingcriticalwill.org/images/documents/Disarmament-fora/ccw/2016/meeting-experts-
laws/statements/12April_UK.pdf
9
http://www.reachingcriticalwill.org/images/documents/Disarmament-fora/ccw/2016/meeting-experts-
laws/statements/12April_Switzerland.pdf
10
http://www.dtic.mil/whs/directives/corres/pdf/300009p.pdf