YJIL Online Symposium: The Blank-Prose Crime of Aggression

YJIL Online Symposium: The Blank-Prose Crime of Aggression


[Michael J. Glennon is Professor of Law at The Fletcher School at Tufts University]

The article addresses a question that is particularly important for the United States. The Obama Administration has begun to express a renewed interest in the International Criminal Court (ICC), after almost a decade of distance between the Court and the United States. But American policy-makers should be wary of a time bomb that could explode in May – the adoption of a vague, new crime of aggression that could have broad application to U.S. leaders.

The United States formally “unsigned” the Court’s foundational Rome Statute in 2002, after President Bill Clinton had initially signed it before leaving office in 2000. Last August, however, Secretary of State Hillary Clinton noted that it is “a great regret . . . that we are not yet a signatory.” State Department representatives have since participated in meetings aimed at preparing for a ten-year review conference to be held in Kampala, Uganda in May. At that conference, member states will consider amending the Court’s Statute by defining a new crime of aggression and permitting the Court to prosecute that crime.

The members’ working group that came up with the new definition has presented it as a major breakthrough. And in a sense it is. International efforts to define a crime of aggression failed repeatedly throughout the 20th century. Sixteen Nazi leaders were tried at Nuremberg for planning, preparing, initiating, or waging a war of aggression, but “aggression” was never defined. The 1945 United Nations Charter proclaimed one of its purposes as “the suppression of acts of aggression,” but, again, left the term undefined. The General Assembly took a crack at defining aggression in 1974 (with the loopy Resolution 3314) – but aggression committed by states, not a crime of aggression committed by individuals. The 1999 Rome conference that drafted the ICC’s Rome Statute listed aggression as one of four crimes prosecutable by the Court but, in the face of U.S. opposition, couldn’t arrive at a definition. Instead, it resolved to revisit the question at the 2010 review conference.

The working group proposes a definition based upon the U.N. Charter―two definitions, actually. An “act of aggression” would represent any use of armed force, and a “crime of aggression” would constitute the planning, preparation, initiation or execution of an act of aggression that is a “manifest” violation of the United Nations Charter. Anyone “in a position effectively to exercise control over or to direct the political or military action of a State” would be guilty of aggression.

The potential breadth of application of the two definitions, taken together, is little short of staggering. Under the proposed definition, every use of force undertaken by the United States in recent decades would constitute an act of aggression. U.S. military actions in the Cuban Missile Crisis in 1962, the Dominican Republic in 1965, Vietnam from 1964 to 1973, Grenada in 1983, Panama in 1989, Sudan in 1998, Afghanistan since 2001, Iraq in 1990 and 2003, Yugoslavia in 1999, Pakistan today―all would represent acts of aggression.

The United States is not the only nation whose actions bring it within the scope of the proposed definition. The 1956 invasion of Egypt by France, the United Kingdom, and Israel, India’s 1971 invasion of East Pakistan, North Vietnamese military actions against South Vietnam from 1960 to 1975, France’s 1979 invasion of the Central African Republic, Vietnam’s 1979 invasion of Cambodia, Tanzania’s 1979 invasion of Uganda, Argentina’s 1982 invasion of the Falklands―and Britain’s response― and Russia’s 2008 invasion of Georgia all represent aggression under the newly proposed definition.

Which of these actions constituted a “manifest” violation of the U.N. Charter? The truth is that it is impossible to say. The Charter prohibits any non-defensive use of force that is not authorized by the Security Council. Yet a U.N. high-level panel found five years ago that violations of the Charter’s use-of-force rules had been so numerous as to defy quantification. By one count, the panel said, from 1945 to 1989 “force was employed 200 times, and by another count, 680 times.” In almost all those instances, the “aggressor state” argued either that it acted in self-defense or under Security Council authorization.

Who within those states exercised control or direction over the military initiatives in question? One can only guess. In modern democracies, preparation for armed conflict engages numerous diplomats, lawyers, intelligence analysts and other administrators. What is clear is that every U.S. President since John F. Kennedy, hundreds of U.S. legislators and military leaders, as well as myriad military and political leaders from other countries would have been subject to potential prosecution had the new definition then been applicable.

The need for guesswork defies standards of criminal liability under international and U.S. law. Basic international human rights norms as well as domestic constitutional guarantees of due process prohibit vague and retroactive criminal punishment. As formulated by the U.S. Supreme Court, a law must “give a person of ordinary intelligence fair notice that his contemplated conduct is forbidden by the statute.” The objective is to discourage arbitrary and discriminatory arrests and prosecutions.

This conclusion is unavoidable: the working group’s definition of the crime of aggression is irretrievably vague. To use the apt phrase of the United States Supreme Court, it fails to provide “ascertainable standards of guilt.” And this infirmity cannot be cured by any of the options under consideration concerning Security Council participation or non-participation in the prosecutorial decision. All come down to two broad alternatives: inclusion or exclusion in the procedure surrounding the decision to prosecute.

Including the Council would cause the prosecutorial process to rest upon a “green light” by the Security Council – a finding that an act of aggression has occurred. But what limits would guide the Council? Under what definition of aggression would it proceed? The answer, of course, is none. The Council is possessed of broad discretion to determine for itself whether conduct in a given instance constitutes an act of aggression. The Council cannot be bound by any definition incorporated in the Rome Statute. As a result, any act of aggression will only be so classified ex post facto, on an ad hoc and subjective basis. The working group can label this as “procedural” or “jurisdictional”, but that does not change its substance: it is a due process problem, akin to prosecuting the crime of loitering only if the specific conduct in question is afterwards denominated loitering by an act of the city council. No amount of re-categorizing or re-labeling can alter the fact that the conduct in question will not have been prosecutable when it occurred.

Excluding the Council, on the other hand, would run afoul of the U.N. Charter. The Charter authorizes the Security Council to “determine the existence of any threat to the peace, breach of the peace, or act of aggression.” Judge Meron has correctly observed that “[t]he [Security] Council’s prerogative to determine the existence of an act of aggression under Article 39 . . . is exclusive.” This is confirmed by the International Court of Justice in the Certain Expenses Case. “[I]t is the Security Council which, exclusively, may order coercive action,” the Court said. “[I]t is the Security Council which is given a power to impose an explicit obligation of compliance if for example it issues an order or command to an aggressor under Chapter VII. It is only the Security Council which can require enforcement by coercive action against an aggressor.” Issuing an indictment for the crime of aggression would represent a coercive order or command executed without the consent of the state in question and therefore could not be carried out independently of the Security Council.

The Charter thus presents the states parties to the Rome Statute with an impossible choice: include the Security Council in the decision to prosecute and create inexorable retroactivity problems, or exclude the Council from that decision and create a structure incompatible with the Charter.

Why should all this matter if the United States continues to refuse to join the Court? The Statute, not surprisingly, is unclear whether the proposed crime would apply to non-parties. Under one plausible reading, however, leaders of non-party states could be prosecuted for the new crime of aggression. In any event, the United States may some day conclude that joining the Court would be profitable. But it will almost surely be impossible to join, politically as well as constitutionally, if this vague and overly-broad definition is adopted.

In the meantime, it makes sense for the United States to participate as an observer in next May’s proceedings to try to steer the Court’s members away from the proposed definition. The 1998 Rome Statute itself requires that it be applied “consistent with internationally recognized human rights.” No right is more fundamental than that of a criminal defendant to know what conduct is illegal at the time the conduct occurs. No one will gain if the Court is permitted to undermine that right.

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Tamás Hoffmann
Tamás Hoffmann

Excluding the Council, on the other hand, would run afoul of the U.N. Charter. The Charter authorizes the Security Council to “determine the existence of any threat to the peace, breach of the peace, or act of aggression.”

This is a confusion of two different concepts. An act of aggression is not necessarily the same as the crime of aggression. GA Res. 3314 first enumerates – though not exclusively – certain categories of acts of aggression, then reaffirms that “war of aggression” is an international crime. So a determination of a crime of aggression does not endanger the competence of the Security Council (which is a political body, not a judicial organ) to determine whether the crime of aggression has been committed.


[…] article, “The Blank-Prose Crime of Aggression.”  Professor Glennon’s initial post has appeared today. The response of Larry Johnson, former UN Assistant-Secretary-General for Legal Affairs, can be […]


[…] at Opinio Juris, an interesting exchange on the question of defining the crime of aggression as part of the International Criminal Court statute.  Professor Michael Glennon discusses his Yale […]


sine lege certa. Glennon’s argument makes sense; including the Council makes the crime uncertain. excluding it makes the definition contrary to intl law


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