How do international laws and the Geneva Conventions affect assessments of lawful military orders?
Executive summary
International humanitarian law (IHL) and the Geneva Conventions set binding rules that define what counts as lawful and unlawful conduct in war and thereby shape when orders can be refused or will expose subordinates to liability (see Geneva Conventions overview [1] and U.S. practice on unlawful orders [2]). The International Committee of the Red Cross’s 2025 updated Commentary on the Fourth Geneva Convention reiterates the protective balance between military necessity and humanity that informs legal assessments of orders [3] [4].
1. What the Geneva Conventions actually do: legal minimums that limit orders
The four 1949 Geneva Conventions and related protocols are treaties forming the backbone of IHL: they establish minimum protections for wounded combatants, prisoners of war, and civilians and require states to criminalize and investigate “grave breaches,” including actions ordered from above [1] [5]. The Conventions thus operate as a legal yardstick: an order to commit conduct that the Conventions categorically prohibit—such as wilful killing of protected persons or extensive unlawful destruction of property—would be unlawful because it contravenes binding treaty obligations [1].
2. How IHL guides the individual soldier’s obligation to disobey
Contemporary U.S. and scholarly materials treat clearly illegal orders—those that violate the Constitution, UCMJ, international human rights norms, or Geneva-derived IHL—as not shielded by the “I was just following orders” defense; service members can be held criminally liable for following such orders [2]. Reporting and surveys of U.S. troops indicate a practical understanding that there is a duty to refuse manifestly illegal commands, and that law, not superior direction, governs criminal responsibility [6] [7] [8].
3. The role of interpretation and the ICRC commentary: ambiguity matters
The Geneva Conventions lay down principles but require interpretation in real-world operations; the ICRC’s updated Commentary on the Fourth Convention compiles decades of state practice and jurisprudence to help practitioners balance military necessity and humanity when applying GC IV protections [3] [4]. That means many orders are not black-and-white: commanders and lawyers must interpret proportionality, distinction, and necessity—areas where reasonable professional disagreement can exist [4].
4. State obligations and enforcement: who judges an order’s lawfulness?
States party to the Conventions must enact and enforce laws penalizing grave breaches and are obligated to search for and prosecute those who commit or order such crimes regardless of nationality or where they occurred [1]. In practice, that creates multiple layers of review: military legal advisers, domestic courts (including courts-martial), and potentially international mechanisms or tribunals can assess whether an order amounted to a grave breach [1].
5. Practical tensions: operational risk, resources and political factors
The Conventions can impose burdens on military operations—caring for POWs or protecting civilians may slow maneuvers or limit tactics—yet these constraints are accepted costs of fighting under a rules-based order [9]. Political leadership, public messaging, and national doctrine can influence how vigorously rules of engagement and Geneva-based limits are interpreted or enforced, creating friction between operational imperatives and legal obligations [9].
6. Why “manifestly illegal” is the key phrase—and why it’s contested
Sources emphasize that the duty to disobey applies to unlawful orders, especially those that are manifestly illegal [2]. But because IHL application often depends on context-specific judgments—distinguishing combatants from civilians, assessing proportionality—what is “manifest” can be disputed. The ICRC’s updated Commentary aims to reduce that uncertainty by consolidating practice and guidance for practitioners [3] [4].
7. Competing perspectives and accountability gaps
Human-rights organizations and some legal scholars press for rigorous enforcement and international scrutiny where states fail to act; others (including some military commentators) stress operational realities and the need for clear, practicable rules of engagement [9] [1]. Available sources document calls for stronger adherence and also record disagreements about how rules affect force employment and national security choices [9] [4].
8. Bottom line for assessments of military orders
The Geneva Conventions and IHL provide binding legal criteria that can render an order unlawful and trigger individual and state responsibility; courts, military lawyers, and international bodies interpret those criteria in practice [1] [5]. Where orders clearly violate the Conventions or constitute “grave breaches,” following them is not a legal defense; in borderline cases, the ICRC’s updated Commentary and established state practice are the reference points for determining lawfulness [1] [3] [2].
Limitations: available sources do not lay out all procedural steps a specific military uses to assess orders in every jurisdiction; they focus on treaty content, ICRC guidance, and U.S. discussion of illegal orders [1] [3] [2].