Skewed Legacy of the American Civil War: Military Advantage in International Humanitarian Law

Introduction

The rule of proportionality, codified in Article 57(2)(b) of Additional Protocol I to the Geneva Conventions, is a central principle of International Humanitarian Law (IHL). It requires military commanders to weigh the concrete and direct military advantage anticipated from an attack against expected collateral harm—namely incidental civilian death, injury, or damage to civilian objects. If the civilian harm would be excessive in relation to the military gain, the attack must be cancelled or suspended.

Together with the rule of distinction—which limits attacks to legitimate military objectives—proportionality forms one of the key protections for civilians during armed conflict.

Yet despite its importance, proportionality has long generated controversy because of uncertainty surrounding the phrase “concrete and direct military advantage.” What counts as military advantage, and how broadly should it be interpreted? This article critiques expansive interpretations that permit attacks on so-called war-sustaining objectives, arguing that they distort IHL’s protective purpose and risk excessive civilian harm.

The Debate over Military Advantage

Under IHL, only military objectives may be lawfully attacked. However, some scholars and state practice have supported a broader reading of military advantage that includes not only direct battlefield assets but also political, economic, social, or psychological contributions to military capacity.

Ryan Goodman distinguishes between:

• War-fighting capabilities – objects directly linked to military operations (for example, fuel for tanks or aircraft).

• War-sustaining capabilities – assets that indirectly support war efforts, such as oil facilities generating revenue for armed forces or political structures maintaining a war-making regime.

Goodman argued that state practice increasingly supports treating war-sustaining objects as lawful targets.

Examples cited include:

• Taliban narcotics revenue networks

• Islamic State petroleum infrastructure

• Operation Desert Storm attacks on Iraqi oil facilities

• Ethiopia attacks on Eritrean power stations during the Eritrea-Ethiopia conflict

The United States Department of Defense Law of War Manual also reflects acceptance of this broader approach.

Critiques of Expansive Targeting

While this trend may influence customary international law, critics warn that it creates a slippery slope. If indirect economic support qualifies as military advantage, then many civilian industries and infrastructures become vulnerable.

This risks transforming ordinary civilian assets into military targets based on speculative or remote links to military capacity.

Historical Roots: The American Civil War

The article traces this reasoning to the American Civil War. During that war, Union forces destroyed Confederate cotton intended for export to United Kingdom. Cotton exports were a key source of Confederate funding for weapons and supplies.

This precedent has been cited by later commentators and military manuals to justify attacks on economic infrastructure that indirectly supports war-making.

The author argues that relying on a single nineteenth-century precedent is problematic, especially since modern humanitarian law developed much later and the United States has not ratified Additional Protocol I.

Modern Consequences

If the “cotton model” is accepted today, then many civilian sectors could become targetable:

• coffee or banana exports funding state revenue

• banks used for tax collection

• commercial centres contributing to the economy

• farms whose taxes support military budgets

Such logic could invert proportionality analysis. Instead of being protected as civilian objects, these assets might be attacked precisely because their destruction creates military advantage.

Jus ad Bellum vs Jus in Bello

The article also criticises arguments that broader targeting rules are justified because certain enemies—such as terrorist groups—commit especially brutal acts.

This, the author argues, improperly merges:

• Jus ad bellum – the law governing when force may be used

• Jus in bello – the law governing how war is fought

A core principle of IHL is that the same humanitarian rules apply to all sides regardless of who started the conflict or whose cause is seen as just.

Allowing moral judgments about the enemy to alter targeting rules would undermine the neutrality and universality of humanitarian protections.

Conclusion

The article concludes that growing acceptance of war-sustaining targets rests on questionable historical precedents and stretches the concept of military advantage beyond IHL’s original purpose: weakening enemy military forces, not destroying civilian economies.

By treating indirect economic activity as targetable, states risk legitimising excessive civilian harm and eroding the protective framework of proportionality.

As warfare increasingly takes place amid civilian populations and infrastructure, the author urges renewed scrutiny of emerging military practices to ensure they remain faithful to the humanitarian foundations of international law.

Surbhi Soni was a final-year BA LLB student at National Law School of India University and focuses on international law and human rights.