The argument for using strikes from unmanned aerial vehicles is that it is not an attack on an individual any more than an artillery barrage that kills a hundred is an attack on each individual. Rather, the jihadist movement presents a unique case in which the individual jihadist is the military unit.
In war, the goal is to render the enemy incapable of resisting through the use of force. In all wars and all militaries, imperfect intelligence, carelessness and sometimes malice have caused military action to strike at innocent people. In World War II, not only did bombing raids designed to attack legitimate military targets kill civilians not engaged in activities supporting the military, mission planners knew that in some cases innocents would be killed. This is true in every military conflict and is accepted as one of the consequences of war.
The argument in favor of using unmanned aerial vehicle strikes is, therefore, that the act of killing the individual is a military necessity dictated by the enemy's strategy and that it is carried out with the understanding that both intelligence and precision might fail, no matter how much care is taken. This means not only that civilians might be killed in a particular strike but also that the strike might hit the wrong target. The fact that a specific known individual is being targeted does not change the issue from a military matter to a judicial one.
It would seem to me that these strikes do not violate the rules of war and that they require no more legal overview than was given in thousands of bomber raids in World War II. And we should be cautious in invoking international law. The Hague Convention of 1907 states that:
The laws, rights, and duties of war apply not only to armies, but also to militia and volunteer corps fulfilling the following conditions:
To be commanded by a person responsible for his subordinates;
To have a fixed distinctive emblem recognizable at a distance;
To carry arms openly; and
To conduct their operations in accordance with the laws and customs of war.
The 1949 Geneva Convention states that:
Members of other militias and members of other volunteer corps, including those of organized resistance movements, belonging to a Party to the conflict and operating in or outside their own territory, even if this territory is occupied, provided that such militias or volunteer corps, including such organized resistance movements, fulfill the following conditions:
(a) that of being commanded by a person responsible for his subordinates;
(b) that of having a fixed distinctive sign recognizable at a distance;
(c) that of carrying arms openly;
(d) that of conducting their operations in accordance with the laws and customs of war.
Ignoring the question of whether jihadist operations are in accordance with the rules and customs of war, their failure to carry a "fixed distinctive sign recognizable at a distance" is a violation of both the Hague and Geneva conventions. This means that considerations given to soldiers under the rules of war do not apply to those waging war without insignia.
Open insignia is fundamental to the rules of war. It was instituted after the Franco-Prussian war, when French snipers dressed as civilians fired on Germans. It was viewed that the snipers had endangered civilians because it was a soldier's right to defend himself and that since they were dressed as civilians, the French snipers -- not the Germans -- were responsible for the civilian deaths. It follows from this that, to the extent that jihadist militants provide no sign of who they are, they are responsible under international law when civilians are killed because of uncertainty as to who is a soldier and who is not. Thus the onus on ascertaining the nature of the target rests with the United States, but if there is error, the responsibility for that error rests with jihadists for not distinguishing themselves from civilians.
There is of course a greater complexity to this: attacking targets in countries that are not in a state of war with the United States and that have not consented to these attacks. For better or worse, the declaration of war has not been in fashion since World War II. But the jihadist movement has complicated this problem substantially. The jihadists' strategy is to be dispersed. Part of its strategy is to move from areas where it is under military pressure to places that are more secure. Thus the al Qaeda core group moved its headquarters from Afghanistan to Pakistan. But in truth, jihadists operate wherever military and political advantages take them, from the Maghreb to Mumbai and beyond.
In a method of war where the individual is the prime unit and where lack of identification is a primary defensive method, the conduct of intelligence operations wherever the enemy might be, regardless of borders, follows. So do operations to destroy enemy units -- individuals. If a country harbors such individuals knowingly, it is an enemy. If it is incapable of destroying the enemy units, it forfeits its right to claim sovereignty since part of sovereignty is a responsibility to prevent attacks on other countries.