Assassination and targeted killing: Law enforcement, execution or self-defence?

During the current round of fighting in the Middle East, Israel has provoked considerable controversy as it turned to targeted killings or assassination to battle militants. While assassination has met with disfavour among traditional observers, commentators have, more recently, sought to justify targeted killings with an appeal to both self-defence and law enforcement. While each paradigm allows the use of lethal force, they are fundamentally incompatible, the former stipulating moral innocence and the latter demanding the presumption of criminal guilt. Putting aside the paradigm of law enforcement which demands due process and forbids extra-judicial execution, the only possible avenue for justifying named killings lies in self-defence. While named killings might be defensible on the grounds that there are no other ways to disable combatants when they fight without uniforms, the costs, including the cost of targeted killing emerging as an acceptable convention in its own right, should be sufficient to view the practice with a good deal of caution.