In her 2003 book Just War Against Terror, Jean Bethke Elshtain argued for a new paradigm for a just war: the fight against global terrorism, particularly terrorism perpetrated by followers of militant Islam. Twenty years after 9/11, this claim is due for revisiting.

Many readers of Providence will be familiar with the general tenets of just war reasoning. In its most basic form, just war reasoning holds that a war is morally justifiable when it meets an ethical threshold for the initiation and conduct of military campaigns.

The jus ad bellum criteria of just cause, sovereign (or legitimate) authority, and right intent help to determine whether reasons for going to war are right. The jus in bello criteria of proportionality of means and noncombatant protection help to determine whether a war was conducted justly, regardless of cause. The developing category of jus post bellum helps to determine the conditions of a just peace, which is the goal of every just war.

These criteria are central to just war reasoning—they separate, we might say, realism from realpolitik—but they are only half the equation. As a form of casuistic (case-based) rather than deontological (rule-governed) moral reasoning, just war thinking also uses paradigm cases as standards. Paradigmatic cases are wars that are widely considered just (positive paradigms) or widely considered unjust (negative paradigms). By comparing new or more controversial casus belli and military tactics to these clear-cut cases, the moral status of a novel conflict can be determined.

Old Paradigms

Prior to the twentieth century, the United States’ key positive paradigms were the War for Independence, which was fought against unjust rule by George III of England, and the Civil War, which was fought to defeat the Confederate slaveocracy.

But by midcentury, the fight against fascism and the need to defend our European allies in World War II had displaced both of these conflicts as the paradigmatic just war: a just cause against a supremely and manifestly unjust foe. Further, the Allied victory in WWII set the stage for a durable peace between former belligerents. Despite some morally questionable tactics, vanishingly few argue the war should not have been fought or the wrong side won.

Yet despite—or perhaps because of—this resounding military success, within a generation the Vietnam War had displaced all other conflicts as the US’s primary negative war paradigm. Vietnam became America’s “never again.” The cultural memory of these two conflicts has shaped American discourse about war ever since. Which of the two conflicts one thinks more truly reflects the soul of America or its military capabilities, very likely determines whether one sees future conflicts as justified—or whether a just war is even possible.

When the first Gulf War happened in 1991, it seemed to me—a teen at the time—that the entire strategy was to avoid another Vietnam. For conducting a short, successful campaign of limited casualties against a clear violation of the territorial sovereignty of a US ally, George H.W. Bush was widely praised.

The War on Terror

The US response to 9/11, however, did not neatly fit either paradigm. As an unprovoked attack on the US mainland resulting in nearly 3,000 civilian casualties, the justness of the cause resembled World War II. As a US military invasion in Asia with an unclear resolution and ever-escalating commitment, it more closely resembles Vietnam.

Fighting the War on Terror is not about defending territory (as in both WWII and Vietnam), in the sense that the September 11 terrorists never intended to invade and rule the cities they attacked, but it is about self-defense (more WWII than Vietnam). As with both World War II (fascism) and Vietnam (communism), the War on Terror has a clear ideological element. The attackers viewed America as the “Great Satan,” setting up themselves as a rival alternative to liberal democracy. Unlike fascism and communism, however, the ideology of militant Islam is not an internal critique.

The War on Terror has several other features that further distinguish it from earlier conflicts:

  • Terror tactics and use of non-regular combatants by the enemy make non-combatant protection more challenging.
  • The enemy moves among states, sometimes without the express acquiescence of the sovereign governments of those territories, expanding and complicating the scope of fighting.
  • An increased use of unmanned aerial vehicles, or drones, and increased targeting of individuals rather than traditional fighting units.
  • Since the enemy is not a sovereign state, victory is more difficult to define.
  • World War II and Vietnam were part of great-power conflicts. The War on Terror looks much more like a global police action.

All of these features suggest that just war thinkers need to view the War on Terror not as an instantiation of twentieth-century paradigms of war, but as a new paradigm altogether. And in casuistry, new paradigms spark new principles, or reinterpretation of existing ones.

New Paradigm, New Principles

Just war principles assume several preconditions: in requiring legitimate authority to commence hostilities, they assume state actors, not transnational or stateless militant groups. They also assume a relative ability to distinguish between combatants and non-combatants—a distinction the 9/11 attackers and related groups routinely blur.

In this context, how should we think about the traditional specification of the jus ad bellum criteria of sovereign (legitimate) authority as requiring an official declaration of war? Does an official declaration become a most-wanted list of approved targets, authorized by a secret court?

The War on Terror also challenges us to expand the definition of just cause. Over the centuries, the set of just causes for war has narrowed, essentially reduced to self-defense or defense of others (sometimes termed the responsibility to protect). But true just wars defend not self, but justice: a just cause for war can be to interdict and punish egregious wrongdoing. If the War on Terror is a just war, it is perhaps more properly a just war of this type—not to defend against invasion, but to bring wrongdoers to account. The War on Terror forces us to think carefully about transnational justice, including how we work with multinational and treaty organizations.

The War on Terror also requires re-examination of the jus in bello criteria of non-combatant protection (discrimination) and proportionality. As dramatized in the film Eye in the Sky, the War on Terror targets people engaged in terrorist activity—individuals who are targets not because they wear the uniform of an enemy state, but because they themselves have done wrong. Unlike the anonymous soldier, the justification for authorizing a targeted killing contains detailed information about an individual, whose responsibility for injustice is known in some specifics. At the same time, remote aerial vehicles have increased our targeting capabilities, while perhaps lowering the costs (financial, material, and collateral) of doing so.

Our response to 9/11—a one-day attack that triggered a two-decade-long active military response—presses us to revisit what success looks like. Is it capturing or killing those responsible for plotting and carrying out terrorist attacks? Degrading the military and technological capabilities of terrorists and their sponsors? Isolating or defeating regimes that provide safe harbor for terrorists? We have to think clearly about the requirements of justice and the costs of executing it, contained in the jus ad bellum prudential consideration of proportionality of ends.

The War on Terror prompts us to reflect more deeply about the interrelated realms of military action, economic sanctions, espionage, and international criminal justice. When is deployment of the military the most proportionate response to terror, and the most likely to succeed? We must not fall prey to the desire for revenge, which can underwrite popular sentiment in favor of a military mobilization, if a military response is neither proportionate or likely to achieve a more just outcome. At the same time, the jus ad bellum prudential criterion of last resort does not require that every other possible response has been tried and failed—only that every other alternative must have been considered and determined to be unworkable.

Post- 9/11 Horizons for Just War Thought

The amorphous and metastatic nature of the War on Terror created a new set of jus in bello cases. Scholars and military professionals are already reflecting on “grey zone” actions—tactics of aggression that fall short of war, or that use unconventional means to achieve a military purpose (cyberwarfare, disinformation, intellectual property theft, ambiguous forces, etc.). Just war scholars will further ask, Are these methods more or less proportional than conventional battles fought with conventional weaponry? Are any acceptable by just war lights?

The US withdrawal from Afghanistan spurs us to think more deeply about the place of jus post bellum and the reasonable hope of success in just war reasoning. If, historically, a morally justifiable war is one which was fought for a just cause and in a just manner, does the lack of an ordered peace—as appears to be the case in Afghanistan, where the Taliban is reviving its despotic ways as it solidifies its grip on the country—make an otherwise just war unjust? If the US and its allies had won the war in Vietnam, and Vietnam (or South Vietnam) today was a stable, democratic nation like German, Japan, or South Korea, would we be more likely to consider it a just war?

This brief examination of just war thinking in light of 9/11 shows us that as a casuistic tradition, just war reasoning is more than a moral checklist. When done well, it illuminates the moral stakes of a particular case and allows us to build upon long-accepted ethical conventions to address novel circumstances. It can also cause us to re-examine old judgments, helping us to see things we did not see before. If we do not engage in this task of revision, we risk misjudging future conflicts: first morally, then practically. And that we cannot afford. Without forgetting their lessons, we must move beyond the paradigms of WWII and Vietnam to establish new paradigms for the twenty-first century.