When War No Longer Follows the Rules: The Challenge of Applying Just War Theory to Non-State Actors in Conflict
When War No Longer Follows the Rules: The Challenge of Applying Just War Theory to Non-State Actors in Conflict
By Robbie Hughes
The international stage is increasingly fraught as state actors confront a new kind of warfare, one that Just War Theory struggles to define: war against non-state actors. Nowhere is this more evident than in Israel’s ongoing conflict with Hamas. The shifting boundaries between military and civilian targets, the asymmetry of power, and the question of proportionality complicate the ethical guidelines that have traditionally governed war. As these lines blur, the applicability of Just War Theory becomes both essential and impossible, challenging the moral foundations of state action in an era where conflict is increasingly defined by non-state actors.
Just War Theory rests on two main pillars: jus ad bellum (the right to go to war) and jus in bello (the right conduct in war), guided by principles of proportionality, legitimate authority, and civilian immunity. These concepts provide moral clarity, assuming the existence of sovereign states accountable under international law. But non-state actors like Hamas operate in a different paradigm—one that defies the fixed borders, clear institutional structures, and combatant distinctions that state actors rely upon. Israel’s military responses to the October 7th attacks, entrenched within densely populated civilian areas, has exposed the moral and strategic quagmire this paradigm shift creates.
One of the key challenges Israel faces is the issue of legitimate authority. While Hamas governs Gaza, many international bodies do not recognize it as a legitimate state actor. However, this lack of recognition does not absolve Hamas of responsibility for its deadly massacre, nor does it excuse Israel from responding. Under traditional Just War Theory, legitimate authority rests with sovereign states. But when a non-state actor like Hamas controls territory and population, the question arises: does the authority shift to this non-state actor, or does it remain with the incumbent state (Israel) or an international governing body?
The broader question is how Just War Theory can be adapted to confront the rise of non-state actors. Israel’s claim to self-defense under jus ad bellum is justifiable—Hamas’ attacks on civilians certainly demand a response. Yet applying jus in bello principles like proportionality and discrimination to asymmetric warfare remains fraught with difficulty. Israel’s military superiority clashes with Hamas’ use of human shields and civilian structures for military operations, raising the question of whether Israeli strikes can ever be “just” under such conditions. Can we truly distinguish combatants from civilians when non-state actors deliberately blur these lines?
This moral dilemma is not confined to Israel. The global rise of terrorism has placed non-state actors at the forefront of international conflict, forcing states to grapple with their ambiguous, ever evolving tactics. The U.S. interventions in Iraq and Afghanistan faced similar challenges, as insurgents blended into civilian populations. The War on Terror was waged on an idea–terrorism–not a state. Similarly, Israel has waged war against Hamas–an idea and self-defined revolutionary movement–which is also not a state. Israel’s war with Hamas is by no means a conventional conflict, making it difficult to apply Just War Theory in ways that align with the realities on the ground.
Israel’s critics argue that its military responses to Hamas are disproportionate, a key tenet of jus in bello. However, proportionality is a slippery concept when applied to non-state actors. Hamas does not field traditional armies; it embeds itself in schools, hospitals, and residential areas, using civilians as shields. Israel’s attempts to target Hamas leaders or destroy rocket-deployment sites often result in civilian casualties, blurring the line between legitimate military targets and unacceptable collateral damage. In a war where one side hides behind civilians, and the other side is expected to strike with surgical precision, the principle of proportionality becomes almost meaningless.
The principle of discrimination—distinguishing between combatants and non-combatants—is equally challenged. In Gaza, where Hamas operates within the civilian population, traditional separations between the two groups hardly exist. Israel’s military strikes are scrutinized, but the expectation that it can wage a “clean” war without harming civilians ignores the tactics employed by non-state actors. This conflict has demonstrated the impossible standards states are held to when engaging with enemies who refuse to follow any rules of warfare.
Critics of Israeli engagement in Gaza often overlook the asymmetric nature of this conflict, applying state-to-state war standards to a conflict that does not fit that mold. But the ethical questions raised by this, and similar conflicts are urgent. How does the international community expect Israel—or any state facing such threats—to respond to an enemy that exploits civilian populations and refuses to follow the rules of war? More importantly, how should Just War Theory evolve to account for this new reality, where non-state actors use war to terrorize and provoke, while evading accountability?
The challenge of applying Just War Theory to non-state actors ultimately demands a rethinking of how we understand conflict in the 21st century. Non-state actors now dominate global conflict, and their methods undermine the traditional moral frameworks that have guided state actors for centuries. Israel’s war with Hamas is not an isolated case but a harbinger of the types of conflicts that will define global politics in the coming decades.
In confronting these questions, we are left with an unsettling truth: Just War Theory, as it stands, is a relic of another time. Its rigid framework, crafted for battles between states, falters in the shadow of modern warfare, where enemies wear no uniforms, and the frontlines are drawn across city streets. To cling to these old rules without adaptation is to remain blind to the brutal realities of today. Israel’s conflict with Hamas begs us to ask uncomfortable questions—not only about the nature of justice in war but about our very ability to discern just from unjust in a world where moral clarity is constantly eroded by unconventional tactics. If we are to preserve any semblance of justice in this new era, we must acknowledge that the battlefield has changed, and so too must our thinking.
Robbie Hughes is a first year Graduate student at the Seton Hall School of Diplomacy & International Relations., specializing in International Human Rights and Foreign Policy. He is editorial board member and Deputy Editor in Chief at the Diplomacy Journal. Robbie completed his bachelor’s degree in Public Policy & Governance from Saint Francis Xavier University in Nova Scotia, Canada.
