The law now generally excuses soldiers who obey a superior's criminal
order unless its illegality would be immediately obvious to anyone on
its face. Such illegality is ''manifest,'' on account of its procedura
l irregularity, its moral gravity, and the clarity of the legal prohib
ition it violates. These criteria, however, often conflict with one an
other, are over- and underinclusive, and vulnerable to frequent change
s in methods of warfare. Though sources of atrocity are shown to be hi
ghly variable, these variations display recurrent patterns, indicating
corresponding legal norms best suited to prevention. There are also d
iscernible connections, that the law can better exploit, between what
makes men willing to fight ethically and what makes them willing to fi
ght at all. Specifically, obedience to life-threatening orders springs
less from habits of automatism than from soldiers' informal loyalties
to combat buddies, whose disapproval they fear. Except at the very lo
west levels, efficacy in combat similarly depends more on tactical ima
gination than immediate, letter-perfect adherence to orders. To foster
such practical judgment in the field, military law should rely more o
n general standards than the bright-line rules it has favored in this
area. A stringent duty to disobey all unlawful orders, coupled to a st
andard-like excuse for reasonable errors, would foster greater disobed
ience to criminal orders. It would encourage a more fine-grained atten
tiveness to soldiers' actual situations. It would thereby enable many
to identify a superior's order as unlawful, under the circumstances, i
n situations where unlawfulness may not be immediately and facially ob
vious to all. This approach aims to prevent atrocity less by increased
threat of ex post punishment, than by ex ante revisions in the legal
structure of military life. It contributes to ''civilianizing'' milita
ry law while nonetheless building upon virtues already internal to the
soldier's calling. In developing these conclusions, the author draws
evidence from a wide array of recent wars and peacekeeping missions.