A Concise History of International Criminal Law

• Pages: 5-42
• Author: Beth Van Schaack,Ronald C. Slye

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Chapter 1

A CONCISE HISTORY OF

INTERNATIONAL CRIMINAL LAW

A. Introduction: The Genesis Story

The international criminal proceedings following World War II

(1939–1945) are credited with launching the modern regime of

international criminal law (ICL). Antecedents, however, trace back

for centuries and across the globe.

1

In particular, ICL draws on four

main strands of international law history: the once theological and

later secular theory of just war, nineteenth-century prohibitions

against piracy, the subsequent regulations of the slave trade and

then slavery, and what we now call international humanitarian law

(IHL) or the “law of war.” On this foundation, the international

community gradually built the norms, rules, instruments, and

institutions that now make up the modern ICL ecosystem. This

chapter interweaves the history of substantive norms with that of

evolving principles of domestic and international jurisdiction, as

these narratives are virtually inseparable in ICL.

Several features of this evolution are worth emphasizing. First,

with the exception of the post-World War II period, when the

international community simultaneously created the law to be

applied and the tribunals to apply it, many ICL norms developed well

before there were judicial institutions available to enforce them. In

the terminology of Professor Dan-Cohn, ICL had conduct rules

without corresponding enforcement rules (rules enabling officials to

enforce the conduct rules).

2

As is the case with much public

international law, it took some time before the international

community was willing to put principle into practice. Second, until

recently, the design of much of the system was ad hoc and reactive to

world events rather than the result of any sort of coherent forward -

looking design process. A notable exception is the permanent

International Criminal Court (ICC), which has only prospective

jurisdiction (i.e., it cannot adjudicate crimes committed prior to its

establishment). Third, the history of ICL is marked by greater and

greater incursions into arenas that were historically the exclusive

province of sovereign states. Thus, not only do ICL norms

increasingly regulate a state’s treatment of its citizens and others

1

See T HE HIDDEN HISTORIES OF WAR CRIMES TRIALS (Kevin Jon Heller &

Gerry Simpson eds., 2013).

2

Meir Dan-Cohn, Decision Rules and Conduct Rules: On Acoustic Separation

in Criminal Law, 97 HARV. L. REV. 625 (1984).

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THE DISCIPLINE OF INTERNATIONAL

CRIMINAL LAW

Pt. I

under its jurisdiction (including non-state actors), but conduct that

violates these norms is increasingly the subject of international

scrutiny, condemnation, and criminal prosecutions.

B. Substantive Law Antecedents to Modern ICL

This short section will highlight elements of the antecedents to

ICL that were available to the architects of the Nuremberg and

Tokyo tribunals as they embarked upon their grand experiment with

international criminal justice. In some respects—for example when

it came to the war crimes provisions within the tribunals’ respective

Charters—the victorious Allies were able to build on a relatively firm

legal foundation. In other respects, however, they had to innovate,

particularly when it came to defining crimes against the peace and

against humanity and building judicial institutions, for which there

was little historical precedent.

1. Just War: The Jus Ad Bellum

Although early Christian theology manifested an “extreme

pacifism” that prohibited participation in war, by the time of St.

Augustine (C.E. 354–430) a theory of just war had developed, which

stated that resort to war was permitted only if the ends were just.

Other religious and national traditions also preserved the right to

engage in war against “infidels” or to avenge a wrong as just ends.

Efforts to identify the necessary conditions for war constitute the jus

(or ius) ad bellum—the set of rules regulating the decision to use

military or armed force in international relations. In his Summa

Theologica, for example, St. Thomas Aquinas (C.E. 1225–1274) set

forth the following requirements for a war to be considered just: (1)

it must be authorized by a legitimate sovereign; (2) it must be

necessary for the achievement of a just cause; and (3) it must be

inspired by a “right intention,” that is the restoration of a good and

just order and not in furtherance of injustice.

3

Self-defense against

an unjust act of aggression, punishment for an unjust act of

aggression, or recovery of something wrongly taken all qualified as

just causes for Aquinas.

By the sixteenth century, however, it became accepted that

there may be a claim of just war on both sides, and the laws of war

gradually shifted attention away from identifying the acceptable

reasons for going to war to regulating the effects of war—the jus (or

ius) in bello. Eventually, the notion of just war dissipated almost

entirely. By the time of World War I, war was viewed as the

prerogative of the sovereign and a valid instrument of foreign policy.

Efforts to “outlaw” war in the form of the Kellogg-Briand Pact,

3

St. Thomas Aquinas, Question 40 of War, in SUMMA THEOLOGICA 1359–1360

(Fathers of the English Dominican Province trans., Benzinger Brothers, Inc. 1947).

Ch. 1

A CONCISE HISTORY OF INTERNATIONAL

CRIMINAL LAW

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promulgated during the interwar period, did little to constrain the

rise of militarism or German and Japanese aggression in World War

II.

4

International law had thus dramatically shifted focus. It went

from evaluating the morality and justice of going to war, but only

weakly regulating the means and methods of warfare, to a

resignation that the justness of war was too difficult to universali ze

combined with renewed efforts to humanize the means and methods

of warfare. This shift in emphasis from the jus ad bellum to the jus

in bello still largely describes the state of the law of armed conflict

today, although the development of the crimes of terrorism and

aggression harkens back to the jus ad bellum tradition.

2. Penal Antecedents: Piracy, the Slave Trade, and Slavery

Piracy and the slave trade were two of the earliest international

crimes outside of war that states coordinated among themselves to

criminalize and prosecute. Up until this point, what we now call ICL

had primarily focused on acts committed by one state against the

nationals of another state in the context of an armed conflict—the

traditional paradigm for war crimes. With the recognition of piracy,

the slave trade, and eventually slavery as international crimes, ICL

turned its attention to private, non-state actors that operated within

the interstitial space separating nation states. With these

prohibitions, we thus see a shift from a focus solely on activity that

is international, or activity between distinct nation states, to an

acceptance of international jurisdiction over activity that affects the

efficient operation of the international system (piracy) or that

implicates universal moral values (slavery and the slave trade).

Piracy was a widespread phenomenon in the eighteenth and

nineteenth centuries. Because piracy was often committed on the

high seas (and thus not within the territorial jurisdiction of any

state), and because there were at first no international tribunals

before which the offender could be prosecuted, any state that

obtained custody of a pirate was permitted to prosecute. The

prohibition against piracy thus gave rise to the notion of universal

jurisdiction—now a central feature of modern ICL. Universal

jurisdiction permits a state to prosecute the perpetrator of certain

crimes that are considered of universal concern to the community of

nations, regardless of the nationality of the perpetrator or victim or

the place of commission.

Piracy was one of the earliest crimes defined internationally and

incorporated by reference into domestic criminal law. In United

4

General Treaty for the Renunciation of War as an Instrument of National

Policy, Aug. 27, 1928, 46 Stat. 2343, 94 L.N.T.S. 57. See OONA HATHAWAY & SCOTT

SHAPIRO, THE INTERNATIONALISTS: HOW A RADICAL PLAN TO OUTLAW WAR REMADE

THE WORLD (2017).