Many Christian responses to the Israel-Hamas conflict lean on just war theory. It’s well intentioned—but deeply flawed.
Just war theory is a venerable Christian tradition. It is the philosophical basis of international and American laws of war and undeniably noble in its intent. But it’s also deeply flawed, and the horrific Israel-Hamas war—to which many Western Christians have responded within a just war framework—demonstrates its limitations anew.
The basic elements of just war theory are two considerations: jus ad bellum (right to war) and jus in bello (right in war). As those phrases suggest in Latin and English alike, it’s about determining whether you have just cause to enter a war and whether you fight justly once the war is underway.
To answer those big questions, just war theorists ask many smaller ones. For jus ad bellum: Is war the option of last resort? Is it publicly declared? Is it declared by a legitimate authority? Is there a just cause? Is there a just goal? Is there a realistic chance of achieving that goal?
Then, for jus in bello: Is the use of force proportionate? Is sufficient care taken to avoid civilian casualties? Are prisoners of war treated humanely? Are war crimes punished by their own country? Is strategy set with an eye to de-escalation wherever possible and, ultimately, a just peace?
Just war theory isn’t monolithic, as probably no theory of this age and import could be, but the basics have been well established for centuries. A classic formulation comes from medieval theologian Thomas Aquinas in his Summa Theologica, building on the work of the early Christian thinker Augustine. You’ll find most iterations run much along these lines.
Just war theory is the intellectual ancestor of the Geneva Conventions—treaties dealing mostly with jus in bello questions that are central …