The Importance of Clarity and Flexibility in the Law

by | Oct 8, 2020

Clarity. U.S. Army soldiers at firing range near Tall Afar, Iraq, on May 13, 2006. DoD photo by Staff Sgt. Jacob N. Bailey, U.S. Air Force


Adherence to the law of armed conflict remains a bedrock value of professional militaries. The legal obligation of any professional military to wage war in a just and lawful manner remains unquestioned. Yet the rules are regularly challenged. In particular, proponents of increased requirements—often in the form of further restrictions—argue that such requirements will better protect innocent civilians. And in some cases, they may.

But ever more legal restraint leads to inherent tension in the system. As every combat-tested leader knows, the enduring reality in armed conflict is an unquestioned necessity for operational flexibility and clarity in fundamental legal requirements. Furthermore, professional militaries operate under the fundamental principle that law of armed conflict restraints apply regardless of the willingness of an opponent to abide by those same restraints. This bedrock principle may undermine the thesis that the uncritical piling on of law of armed conflict restraints necessarily leads to less costly war.

Trained, battle-tested soldiers with moral clarity understand these concerns. But this is not enough, because differences in the understanding between militaries and the societies they serve over the scope of the fundamentals of the law governing military force are at best precarious. At its worst—however well-intentioned—confusion further burdens those in the greatest immediate risk of physical danger with a corresponding risk of long-term legal jeopardy to the continued and proper functioning of the legal order during and after combat.

Rapid, exponential advances in technology, or even new techniques in the asymmetric employment of simpler, long-standing technology, routinely create new challenges to the law’s scope, meaning, and application. Even with such changes, lex lata remains the coin of the realm. Visionary senses of lex ferenda are often well-received by the body politic. However gallant the intent, foundational legal principles must remain inviolate. Attempting to reframe the moral or ethical application of the law of armed conflict may undermine the decision-making space of commanders, reduce their flexibility, and, as an unintended consequence, limit the options they have to lawfully, effectively, and quickly eliminate an opposing force and hopefully set conditions favorable to a return to law and order.

Francis Lieber’s General Orders No. 100 and the World War II-era Hostage Case (at p 1253) reiterated one of two important law of armed conflict realities: military necessity permits a belligerent, subject to the law of armed conflict, to apply any amount and kind of force to compel the complete submission of the enemy with the least possible expenditure of time, life, and money. The second reality is equally brutal in that the restraint imposed by the principle of proportionality requires combatants to refrain from attacks in which the expected loss or injury to civilians and damage to civilian objects incidental to such attacks would be excessive in relation to the concrete and direct military advantage expected to be gained. Yet, injury—even death—and damage—even great damage—are not only not prohibited but expected under certain circumstances.

The continuing dialogue about the nature and content of the law of armed conflict owes much of its impassioned advocacy to this confluence of the long-standing clarity that results in well-trained practice and the desire to always do more and do better. In the discussion, practitioners must listen; advocates must too. We all should build upon the robust body of previous work and critically address the challenges professional armies already face in the conduct of hostilities. In doing so, it is important to reflect on the experiences of military practitioners and the intellectual thought of noteworthy scholars. They can help frame the discussion necessary to arm our Nation’s and the allies and partners alongside whom we fight, with the clearest possible understanding of what the law requires.

That clarity informs the training that, in the moment, allows those uniquely tasked with the lawful application of lethal violence, to get it right. From our Nation’s earliest days, and through even our darkest hours, advisors like Francis Lieber ensured leaders like Abraham Lincoln made clear our shared commitment to established legal standards in warfare. The commitment endures. This dialogue must inform it.


This article was taken (and slightly adapted) from the forward to the forthcoming Lieber Studies Series Volume V: Military Necessity and Proportionality in International Peace and Security Law, published by OUP.


Brigadier General Joe Berger currently serves as the Commander of The Judge Advocate General’s Legal Center and School.