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" ! COMMITTEE PRINT 

111TH CONGRESS

2d Session 

S. PRT. 

2010

111–55 

INTERNATIONAL CRIMINAL COURT 

REVIEW CONFERENCE 

KAMPALA, UGANDA 

MAY 31– JUNE 11, 2010 

A JOINT COMMITTEE STAFF TRIP REPORT 

PREPARED FOR THE USE OF THE

COMMITTEE ON FOREIGN RELATIONS 

UNITED STATES SENATE 

ONE HUNDRED ELEVENTH CONGRESS

SECOND SESSION

SEPTEMBER 2, 2010 

Printed for the use of the Committee on Foreign Relations 

Available via World Wide Web: 

http://www.gpoaccess.gov/congress/index.html 


seneagle
COMMITTEE ON FOREIGN RELATIONS 

JOHN F. KERRY, Massachusetts, Chairman 

CHRISTOPHER J. DODD, Connecticut 

RUSSELL D. FEINGOLD, Wisconsin 

BARBARA BOXER, California 

ROBERT MENENDEZ, New Jersey 

BENJAMIN L. CARDIN, Maryland 

ROBERT P. CASEY, JR., Pennsylvania 

JIM WEBB, Virginia 

JEANNE SHAHEEN, New Hampshire 

EDWARD E. KAUFMAN, Delaware 

KIRSTEN E. GILLIBRAND, New York 

RICHARD G. LUGAR, Indiana 

BOB CORKER, Tennessee 

JOHNNY ISAKSON, Georgia 

JAMES E. RISCH, Idaho 

JIM DEMINT, South Carolina 

JOHN BARRASSO, Wyoming 

ROGER F. WICKER, Mississippi 

JAMES M. INHOFE, Oklahoma 

FRANK G. LOWENSTEIN, Staff Director 

KENNETH A. MYERS, JR., Republican Staff Director 

(II)

C O N T E N T S 

Page 

Letter of Transmittal ............................................................................................... v 

Background .............................................................................................................. 1 

Pre-Conference Discussions of Agression .............................................................. 1 

Historical U.S. Position on Aggression .................................................................. 3 

The Obama Adminstration’s Approach to the Kampala Conference ................... 4 

Discussions on Aggression at the Kampala Conference ....................................... 6 

Outcome .................................................................................................................... 8 

Analysis of Outcome ................................................................................................ 9 

Implications for the United States .................................................................. 9 

Implications for the ICC .................................................................................. 11 

Further Observations on the Negotiation Process ................................................ 11 

Annex—ICC Review Conference Decision on Aggression ..................................... 13 

(III)

LETTER OF TRANSMITTAL 

UNITED STATES SENATE, COMMITTEE ON FOREIGN RELATIONS, Washington, DC, September 2, 2010. 

DEAR COLLEAGUES: In May 2010, we directed two members of 

the Foreign Relations Committee staff, Minority Chief Counsel 

Michael Mattler and Majority Deputy Chief Counsel Andrew Keller, to observe U.S. participation at the Review Conference of the 

Rome Statute of the International Criminal Court (ICC), which 

took place in Kampala, Uganda, from May 31–June 11, 2010. The 

conference represented the first time parties to the ICC considered 

amendments to the Rome Statute since it entered into force in 

2002. We thank the co-heads of the U.S. delegation, State Department Legal Adviser Harold Koh and Ambassador at Large for War 

Crimes Issues Stephen Rapp, along with their colleagues from the 

Departments of State, Defense, and Justice, for including Mr. 

Mattler and Mr. Keller as part of the U.S. delegation. 

The United States is not a party to the ICC, and is unlikely to 

become a party anytime soon. Nonetheless, the United States had 

interests at stake in the discussions at Kampala. The principal 

focus of the Kampala Conference was consideration of proposals to 

add to the ICC’s jurisdiction a new crime of aggression, some of 

which could have seriously affected uses of military force by the 

United States and its allies. The United States also had an interest 

in better understanding the state of the ICC’s work generally, and 

its prospects for making an effective contribution to promoting accountability for genocide, war crimes, and crimes against humanity. In this regard, the United States, under both the George W. 

Bush and Obama administrations, has supported the ICC’s investigation of such crimes in Darfur, pursuant to a 2005 referral by 

the U.N. Security Council. 

As this report highlights, the Kampala Conference adopted a 

complicated decision that envisions the future addition of a crime 

of aggression to the ICC’s jurisdiction. The proposed aggression regime is flawed in several respects, but nonetheless contains important protections for U.S. interests. Most significantly, U.S. persons, 

including U.S. officials and military members, could not be investigated or prosecuted for aggression by the ICC without the consent 

of the United States. The proposed regime will not enter into force 

for at least seven years, and will do so only after a further decision 

by the ICC’s parties to bring it into force. U.S. participation at the 

Kampala Conference played an important role in securing these 

protections. 

(V) 

vi 

The report also observes that, with the Conference’s focus on 

adding a new crime to the ICC’s mandate, ICC parties spent comparatively little energy at the Conference addressing a range of 

operational challenges currently faced by the Court. Eight years 

after entering into force, the ICC has yet to complete its first trial 

and is encountering a variety of practical obstacles to its effectiveness. Absent greater focus on addressing such difficulties in the 

ICC’s operations, the court may continue to struggle in carrying out 

its basic judicial functions. 

We hope you find this report useful and informative. We welcome 

any comments you may have on it. 

Sincerely, 

JOHN F. KERRY, 

Chairman. 

RICHARD G. LUGAR, 

Ranking Minority Member. 

(1) 

INTERNATIONAL CRIMINAL COURT 

REVIEW CONFERENCE 

KAMPALA, UGANDA, MAY 31– JUNE 11, 2010 

BACKGROUND

The International Criminal Court was established in 1998. 

Under the treaty establishing the ICC, known as the Rome Statute, 

the Court has jurisdiction to investigate and prosecute cases of 

genocide, war crimes, and crimes against humanity. The treaty entered into force in 2002 and currently has 113 states parties. The 

United States is not a party to the ICC. 

On May 31, 2010, the parties to the ICC convened a 2-week conference to assess the work of the ICC since its inception and to consider amendments to the Rome Statute. The United States sent a 

delegation to the conference and participated as an observer. 

The principal issue before the conference was whether to amend 

the Rome Statute to add a new crime—aggression—to the ICC’s jurisdiction. The conference also considered two more technical 

amendments to the statute, and held a series of moderated discussions to take stock of elements of the ICC’s performance to date. 

The stocktaking discussions addressed the relationship between the 

court’s work and broader efforts to resolve conflict and restore 

peace, the impact of the court’s work on victims of crimes, the extent of cooperation with the court by states, and efforts by states 

to establish accountability for serious crimes at the national level. 

This report addresses the Conference’s discussions and decisions 

related to the crime of aggression. 

PRE-CONFERENCE DISCUSSIONS OF AGGRESSION

As adopted in 1998, the Rome Statute gave the ICC jurisdiction 

over three crimes: genocide, war crimes, and crimes against humanity. At the Rome Conference, negotiators discussed giving the 

court jurisdiction over the additional crime of aggression, but were 

unable to agree on a definition of the crime or on the conditions 

under which the ICC might exercise jurisdiction over it. As a compromise, the Rome Statute provided that the ICC could exercise jurisdiction over aggression in the future if the statute were amended 

to address these issues. 

Following the Rome Conference, the ICC’s Assembly of States 

Parties established a special working group on the crime of aggression. The working group met between 2003 and 2009 and developed proposals on both a definition of the crime aggression and on 

conditions under which the ICC might exercise jurisdiction over it. 

The United States did not participate in the working group. The 

working group’s proposals are described briefly below. 

2 

Definition of Aggression—In contrast to the other crimes within 

the ICC’s jurisdiction, aggression has not previously been widely 

employed as a criminal law concept in domestic or international 

law. In the aftermath of World War II, the International Military 

Tribunals in Nuremburg and Tokyo prosecuted a few German and 

Japanese officials for ‘‘crimes against peace,’’ though there was no 

widely agreed definition of this concept prior to the war. Following 

the war, the U.N. Charter gave the Security Council the authority 

to determine when a state had committed an ‘‘act of aggression’’ 

and to decide on measures to be taken to restore international 

peace and security. But the Charter’s treatment of aggression does 

not provide for criminal liability on the part of individuals. 

The working group recommended a definition based largely on a 

1974 U.N. General Assembly resolution, which was adopted for the 

purpose of providing guidance to the U.N. Security Council’s use in 

determining whether a state had committed aggression for the purposes of the U.N. Charter. The working group’s definition reads as 

follows: 

ARTICLE 8 BIS—CRIME OF AGGRESSION

1. For the purpose of this Statute, ‘‘crime of aggression’’ means the planning, 

preparation, initiation or execution, by a person in a position effectively to exercise 

control over or to direct the political or military action of a State, of an act of aggression which, by its character, gravity and scale, constitutes a manifest violation of 

the Charter of the United Nations. 

2. For the purpose of paragraph 1, ‘‘act of aggression’’ means the use of armed 

force by a State against the sovereignty, territorial integrity or political independence of another State, or in any other manner inconsistent with the Charter of the 

United Nations. Any of the following acts, regardless of a declaration of war, shall, 

in accordance with United Nations General Assembly resolution 3314 (XXIX) of 14 

December 1974, qualify as an act of aggression: 

(a) The invasion or attack by the armed forces of a State of the territory of 

another State, or any military occupation, however temporary, resulting from 

such invasion or attack, or any annexation by the use of force of the territory 

of another State or part thereof; 

(b) Bombardment by the armed forces of a State against the territory of another State or the use of any weapons by a State against the territory of another State; 

(c) The blockade of the ports or coasts of a State by the armed forces of another State; 

(d) An attack by the armed forces of a State on the land, sea or air forces, 

or marine and air fleets of another State; 

(e) The use of armed forces of one State which are within the territory of another State with the agreement of the receiving State, in contravention of the 

conditions provided for in the agreement or any extension of their presence in 

such territory beyond the termination of the agreement; 

(f) The action of a State in allowing its territory, which it has placed at the 

disposal of another State, to be used by that other State for perpetrating an act 

of aggression against a third State; 

(g) The sending by or on behalf of a State of armed bands, groups, irregulars 

or mercenaries, which carry out acts of armed force against another State of 

such gravity as to amount to the acts listed above, or its substantial involvement therein. 

Three key elements are at the core of the proposed definition: 

First, aggression is a crime committed by political or military 

leaders—such as heads of state or senior military officials—who, on 

behalf of a state, plan or direct acts of aggression carried out by 

others. Aggression is not committed by officials or soldiers carrying 

out the decisions of others. 

3 

Second, aggression involves the use of force in violation of the 

U.N. Charter. Under the U.N. Charter, states are prohibited from 

using force against the territorial integrity or political independence of another state except in self-defense from an armed attack 

or if authorized by the U.N. Security Council. 

Third, aggression arises only in the case of ‘‘manifest’’ violations 

of the U.N. Charter, meaning that the character, gravity, and scale 

of the violation are clearly established. 

Conditions for the Exercise of Jurisdiction Over Aggression—The 

working group was unable to arrive at a consensus recommendation regarding the conditions under which the ICC might exercise 

jurisdiction over aggression. Delegations fell broadly into two 

camps on this issue. 

Permanent members of the U.N. Security Council took the position that the ICC should exercise jurisdiction over aggression only 

in cases in which the U.N. Security Council had specifically asked 

it to do so. The U.N. Charter vests the Security Council with the 

responsibility for determining the existence of an act of aggression, 

and measures to be taken to maintain or restore international 

peace and security. An independent role for the ICC in investigating and prosecuting aggression could prejudice the Council’s 

efforts to resolve situations involving potential aggression and create the risk of broader conflict. 

Most other countries supported some authority for the ICC to exercise jurisdiction over aggression independently of the U.N. Security Council. These countries were concerned that a deadlock in the 

Security Council over a particular case would prevent the ICC from 

being able to address a case of aggression. They also argued that 

the Security Council’s involvement in deciding whether cases could 

proceed would inject political considerations into judicial matters 

and undermine the integrity of the ICC’s proceedings. 

HISTORICAL U.S. POSITION ON AGGRESSION

While the United States did not participate in the work of the 

Assembly of States Parties’ special working group on aggression, 

the United States has historically expressed concerns about proposals to include aggression within the ICC’s jurisdiction. 

In 1998 testimony before the Senate Foreign Relations Committee, the Clinton administration’s chief negotiator at the Rome 

Conference, David Scheffer, expressed the following set of concerns 

about the treatment of aggression in the original Rome Statute: 

We are disappointed with the treatment of the crime of 

aggression. We and others had long argued that such a 

crime had not been defined under customary international 

law for purposes of individual criminal responsibility. We 

also insisted, as did the International Law Commission in 

1994, that there had to be a direct linkage between a prior 

Security Council decision that a state had committed aggression and the conduct of an individual of that state. The 

statute of the court now includes a crime of aggression, but 

leaves it to be defined by a subsequent amendment to be 

adopted 7 years after entry into force. There is no guarantee that the vital linkage with a prior decision by the 

4 

1Statement of David Scheffer, Ambassador at Large for War Crimes Issues, to the U.S. Senate 

Committee on Foreign Relations, July 23, 1998. 2 22 U.S.C. § 7421 et seq. 

Security Council will be required by the definition that 

emerges, if in fact a broadly acceptable definition can be 

achieved. We will do all we can to ensure that such linkage survives.1

This statement reflected two principal concerns at the heart of 

the U.S. position: 

First, the United States has expressed concerns that aggression 

has not been sufficiently defined to form an appropriate basis for 

criminal prosecutions. Prosecutions based on a definition of aggression that does not reflect customary international law would create 

the risk that individuals could face criminal penalties for uses of 

force that have not traditionally been considered unlawful by the 

international community. This could serve to discourage a wider 

range of uses of force than are prohibited under existing customary 

international law, including some that may be necessary to protect 

the security interests of the United States and its allies. In addition, in the absence of a clear and accepted definition of the crime, 

potential defendants would not have clear guidance about what actions are prohibited, raising fundamental questions of fairness and 

due process in any criminal proceedings. 

Second, the United States has expressed concerns about the potential impact of an ICC crime of aggression on the role and authority of the U.N. Security Council. As a permanent member of 

the Security Council, the United States has an interest in ensuring 

that actions by the ICC in relation to alleged cases of aggression 

do not interfere with the Council’s own efforts to address matters 

of international peace and security. 

In addition to these considerations, U.S. policy has also stressed 

a strong interest in protecting U.S. persons, including U.S. officials 

and members of the armed forces, against potential ICC investigations or prosecutions for aggression, which may be unfounded or 

politically motivated. As a nonparty to the ICC, the United States 

has long objected to any efforts by the ICC to assert jurisdiction 

over Americans with respect to its core crimes of genocide, war 

crimes, and crimes against humanity. Securing protections against 

such assertions of jurisdiction by the ICC was a core objective of 

the American Servicemembers’ Protection Act, passed by Congress 

in 2002.2 Concerns about U.S. exposure to an ICC regime for aggression would be especially acute, given that aggression cases 

would involve potential criminal prosecution of the President and 

other senior political and military leaders for their decisions and 

actions related to matters of U.S. national security. 

THE OBAMA ADMINISTRATION’S APPROACH TO THE KAMPALA

CONFERENCE

The administration’s decision to attend the Kampala Conference 

as an observer reflected two principal considerations. First, the administration sought to address U.S. concerns and protect U.S. interests with respect to the proposed ICC aggression regime, including those discussed above. Second, the administration sought to exVerDate Nov 24 2008 17:33 Sep 01, 2010 Jkt 000000 PO 00000 Frm 00010 Fmt 6633 Sfmt 6602 S:\HEARING FILES\STAFF REPORTS\KAMPALA.TXT SENFOR1 PsN: BETTY
5 

press and reinforce longstanding U.S. support for efforts to promote 

accountability for international crimes such as genocide, crimes 

against humanity, and war crimes. This included exploring ways in 

which the United States, as a nonparty to the ICC, could work with 

ICC members to advance shared objectives in this area. 

Consistent with these objectives, the United States delegation in 

Kampala raised a series of concerns in connection with the conference’s consideration of the crime of aggression. These concerns 

fell into four main categories: 

Concerns With the Content of the Definition—The U.S. delegation 

observed that the proposed aggression definition was vague in a 

number of respects, creating uncertainty on several important 

issues. They noted that the proposed definition applied to ‘‘acts of 

aggression’’ rather than ‘‘wars of aggression’’ that were the subject 

of prosecution at Nuremburg, leaving unclear the scope of the 

crime. They also noted that it was unclear how the term ‘‘manifest’’ 

in the definition would apply, including whether it must be shown 

that a state was ‘‘manifestly’’ not acting in self-defense or with the 

consent of the state where force was used. It was also unclear how 

the ‘‘manifest’’ standard would apply in cases where force was used 

for the purpose of preventing serious crimes such as genocide, war 

crimes, and crimes against humanity. The U.S. delegation also 

noted ways in which the definition departed from existing customary international law, as well as from the General Assembly 

Resolution on which the definition was based. These included the 

definition’s failure to specify that only the most serious and dangerous forms of illegal uses of force constitute aggression, with the 

determination whether an act of aggression has occurred requiring 

careful consideration of the circumstances of each particular case, 

including the purpose for which force was used. 

Concerns With the Conditions for the Exercise of Jurisdiction 

Over Aggression—Consistent with the historical U.S. position, the 

U.S. delegation took the position that a prior decision of the U.N. 

Security Council that aggression had occurred should be a precondition to the ICC’s exercise of jurisdiction over the crime of 

aggression in any case. The delegation opposed proposals for alternative jurisdictional schemes in which the ICC could exercise jurisdiction over aggression without prior Security Council approval, 

including proposals in which the ICC Prosecutor could proceed with 

cases after a period of notice to the Security Council unless the 

Council affirmatively decided that the case should not proceed. The 

U.S. delegation also stressed longstanding U.S. concerns about any 

effort to subject states to ICC jurisdiction over aggression without 

their consent, except in cases of referral by the U.N. Security Council. 

Concerns With the Impact of the ICC’s Aggression Regime for National Justice Systems—The U.S. delegation expressed concern that 

adding aggression to the Rome Statute could lead to efforts by individual states to prosecute leaders of other countries for aggression 

through their national courts. This risk arises because, under the 

Rome Statute, the ICC is a court of last resort and may exercise 

jurisdiction over a crime only where relevant states are unwilling 

or unable to investigate and prosecute them through their national 

justice systems. Under this system, states are encouraged to prosVerDate Nov 24 2008 17:33 Sep 01, 2010 Jkt 000000 PO 00000 Frm 00011 Fmt 6633 Sfmt 6602 S:\HEARING FILES\STAFF REPORTS\KAMPALA.TXT SENFOR1 PsN: BETTY
6 

ecute crimes domestically rather than requiring recourse to the 

ICC. The U.S. delegation expressed concerns that encouraging domestic prosecutions of aggression, which could involve two countries to a conflict each trying to prosecute the other’s leaders in its 

own courts, could exacerbate tensions and undermine international 

peace and security. 

Concerns With the Process for Making Decisions About Aggression—In light of the divergent views over the circumstances in 

which the ICC might exercise jurisdiction over aggression, the U.S. 

delegation also stressed the importance that any decisions be based 

on a consensus among ICC members (which would necessarily include the United Kingdom and France, which are permanent members of the U.N. Security Council). The U.S. delegation observed 

that all prior Rome Statute crimes had been adopted by consensus 

and that adoption of a regime for the politically charged crime of 

aggression over the objections of some countries would undermine 

the legitimacy of both the crime and the ICC itself. 

DISCUSSIONS ON AGGRESSION AT THE KAMPALA CONFERENCE

The negotiations at the Kampala Conference focused on four 

principal issues: the content of the definition of aggression, the conditions for the exercise of jurisdiction over aggression, whether the 

aggression regime would apply to states that had not consented to 

it, and the process for adopting amendments to the Rome Statute 

regarding aggression. 

Content of the Definition—In spite of U.S. criticism of the definition of the crime of aggression proposed by the Assembly of States 

Parties’ special working group, the definition itself was widely supported at the conference, including by U.S. allies such as the 

United Kingdom and France. This support did not appear to be 

based on substantive disagreement with the questions raised by 

the United States about the definition. Instead, it seemed to reflect 

concern that reopening the definition would delay the process of 

reaching a final decision on aggression (to which many countries 

were firmly committed) and that other compromises that had been 

made in arriving at the proposed definition might be revisited if 

the text were reconsidered. 

While the Conference was accordingly unwilling to entertain 

changes to the definition’s text, delegations were willing to discuss 

adopting ‘‘understandings’’ addressing elements of the definition. 

Such understandings were viewed as a means of providing authoritative guidance to the ICC Prosecutor and judges on interpretive 

issues related to the definition. The United States proposed a series 

of understandings to address concerns it had raised about the definition. These included understandings designed to provide greater 

clarity about the meaning of a ‘‘manifest’’ violation of the U.N. 

Charter as used in the definition, to specify that an ICC aggression 

regime would not create the right or obligation for states to exercise domestic jurisdiction over alleged acts of aggression by other 

states, and to provide greater specificity about the level of gravity 

required to establish the existence of aggression. 

Conditions for the Exercise of Jurisdiction—This represented the 

most contentious issue of the conference. Most delegations opposed 

the position of the five permanent members of the Security Council 

7 

that the ICC Prosecutor should have authority to investigate and 

prosecute aggression only in cases where the Council had previously determined that a state had committed an act of aggression. This majority view reflected a concern that the ICC’s judicial 

role required it to operate independently from political constraints. 

It also reflected deep dissatisfaction with the Security Council 

among developing countries, and concern that Security Council decisions would reflect the interests of the five permanent members 

rather than the interests of the international community as a 

whole. 

Most delegations proposed giving the Security Council at most a 

fixed period of time to determine whether a state had committed 

aggression in connection with a situation in which the ICC Prosecutor wished to investigate or prosecute an individual for aggression. In the absence of a determination by the Security Council by 

the end of the time period, these countries urged that the Prosecutor have the authority to move forward with the case on his own 

initiative. 

Consent Requirement—Delegations differed over whether a state 

must have consented to the ICC’s aggression jurisdiction in order 

for its nationals to be subject to investigation and prosecution for 

aggression by the ICC. States were more divided on this question 

than on the question related to the role of the Security Council. In 

general most countries, particularly those in the developing world, 

opposed a requirement that a state consent before an aggression 

regime would apply to its nationals. They argued that prosecutions 

for aggression would be less likely, and the deterrent created by 

the regime less effective, if it applied only to states that had consented. A sizeable minority, including a number of European countries, supported a consent requirement, arguing that such consent 

is a basic requirement to bind a state under international law. All 

delegations agreed that no state consent would be required where 

the ICC was prosecuting aggression at the request of the U.N. 

Security Council, which has the authority to bind U.N. member 

states pursuant to the U.N. Charter. 

Process for Adopting Amendments Related to Aggression—Delegations also differed over the correct process for amending the Rome 

Statute to address aggression. At issue in the debate were two alternative methods provided for under the Rome Statute for adopting amendments. Under the first method, contained in Article 121, 

paragraph 4, amendments are binding on all Rome Statute parties 

once they have been approved by 7⁄8 of the states parties. Under 

the second method, contained in Article 121, paragraph 5, amendments are binding only on those states that have accepted them. 

Delegations’ positions on these procedural questions often mirrored their positions on whether state consent should be required 

for the ICC to have jurisdiction over the state’s nationals. States 

opposed to a consent requirement tended to favor an amendment 

process that would bind all states so that an aggression regime 

could apply universally even if a minority of states objected to it 

and declined to ratify it. Supporters of a consent requirement generally supported an amendment process in which amendments 

would apply only to those states that ratified them, so that nonVerDate Nov 24 2008 17:33 Sep 01, 2010 Jkt 000000 PO 00000 Frm 00013 Fmt 6633 Sfmt 6602 S:\HEARING FILES\STAFF REPORTS\KAMPALA.TXT SENFOR1 PsN: BETTY
8 

ratifying states could avoid being bound by a regime that was 

adopted over their objections. 

OUTCOME

Discussions at the Kampala Conference were unable to fully resolve the most contentious issues related to the proposed aggression regime. The Conference adopted a complicated decision that 

reflected compromises on several key issues. The decision provides 

that the envisioned aggression regime will not become operational 

for at least seven years, and even then only after a further decision 

by the ICC’s Assembly of States Parties to bring it into effect. The 

text of the decision is attached as an annex to this report. Below 

is a summary of the key provisions of the decision: 

Definition of Aggression—The Conference adopted the definition 

of aggression proposed by the Working Group without any amendment. In an effort to address concerns raised by the U.S. delegation 

about lack of clarity in aspects of the definition, the Conference 

adopted a series of interpretive understandings relating to aspects 

of the definition. Among the approved understandings were: 

• An understanding specifying that, in assessing whether an act 

of aggression constitutes a ‘‘manifest’’ violation of the U.N. 

Charter, the character, gravity, and scale of the act must all 

be considered, and that no one of these elements by itself can 

satisfy the ‘‘manifest’’ standard; 

• An understanding specifying that only the most serious and 

dangerous forms of the illegal use of force constitute aggression, and that determinations of aggression require considering 

all the relevant circumstances of each case, including the gravity of the acts and their consequences; and 

• Two understandings specifying that the amendments address 

the crime of aggression only for the purpose of the Rome Statute, and that they shall not be interpreted as creating the right 

or obligation for states to exercise domestic jurisdiction over 

alleged acts of aggression by other states. 

Conditions for the Exercise of Jurisdiction Over Aggression—The 

Conference adopted two separate procedures for the ICC to exercise 

jurisdiction over aggression. Under the first, the Court could exercise jurisdiction in cases specifically referred to the ICC by the 

U.N. Security Council. Under the second, the Court could exercise 

jurisdiction when requested by a state in which aggression is alleged to have occurred, or when the ICC Prosecutor decides on his 

own initiative to pursue a case. In the latter two cases, before an 

investigation may commence, the ICC Prosecutor must consult the 

U.N. Security Council and may only proceed if the Council either 

determines that the case involves a situation in which a state has 

committed aggression or fails to make any determination on this 

question. Where the Council makes no determination, the Prosecutor must receive authorization from a Pre-Trial Chamber of ICC 

Judges before he may commence an investigation. Where the Prosecutor proceeds with an investigation in the absence of an affirmative Security Council determination that aggression has occurred, 

the Council may pass a resolution suspending the investigation for 

1 year, and may renew such a suspension for subsequent periods. 

9 

Consent Requirement—The decision adopted by the Conference 

allows states parties to the ICC to decline to accept the ICC’s jurisdiction over aggression in cases that have not been referred by the 

U.N. Security Council. Similarly, the decision also specifies that 

the ICC shall not exercise jurisdiction in respect of alleged aggression committed by the nationals or on the territories of states that 

are not parties to the ICC, except where referred by the U.N. Security Council. All states would be subject to the ICC’s aggression 

jurisdiction in cases referred by the Security Council. 

Procedure for Adopting Amendments and Entry into Force—The 

decision adopted by the Conference provides for the relevant 

amendments to the Rome Statute to be adopted under Article 

121(5) of the Rome Statute, meaning that the amendments will 

apply only to those states parties to the Rome Statute that approve 

them and not to those that decline to ratify. In addition, the 

amendments establish two additional requirements before they 

may enter into force. First, they will apply only to acts of aggression committed one year after 30 states have ratified them. Second, 

the ICC won’t exercise jurisdiction over aggression until a decision 

is taken by the ICC parties, no earlier than January 1, 2017, to 

bring the ICC’s aggression regime into effect. 

ANALYSIS OF OUTCOME

The Kampala Conference’s outcome on aggression has implications for both the United States and the ICC. These are discussed 

below. 

Implications for the United States 

1. Exemption for Non-States Parties—The most significant aspect 

of the outcome for the United States is its elimination of any risk 

that U.S. officials will be subject to prosecution for aggression by 

the ICC absent U.S. consent. The decision of the Assembly of 

States Parties exempts from key aspects of the ICC’s aggression jurisdiction actions committed by the nationals or on the territories 

of countries, including the United States, that are not parties to 

the ICC. Such nonparties could only be prosecuted by the ICC for 

aggression in cases referred by the U.N. Security Council; they 

could not be prosecuted solely at the request of another country or 

by the ICC Prosecutor on his own initiative. Because the United 

States is a permanent member of the U.N. Security Council and 

has a veto over its decisions, the Council could not refer an aggression case involving U.S. officials to the ICC over the objection of 

the United States. 

With respect to other crimes in the ICC’s jurisdiction—genocide, 

war crimes, and crimes against humanity—the Rome Statute purports to give the ICC authority to prosecute nationals of countries 

that are not parties to the ICC without approval of the Security 

Council. As a nonparty, the United States has strenuously objected 

to this claim, and it has been a source of significant friction between the United States and the ICC. The ICC’s decision not to repeat its claim of jurisdiction over nationals of nonparties when designing its aggression regime avoids a reigniting of this contentious 

issue. 

10 

2. Potential Impact on Coalition Activities—Because many U.S. 

allies, including all NATO members except Turkey, are parties to 

the ICC, they would be potentially subject to the ICC’s aggression 

jurisdiction once it is brought into effect. This could make some 

U.S. allies more hesitant to join with the United States in uses of 

force without clear U.N. Security Council approval, as was the case 

with the 1999 NATO military actions in Kosovo and the 2003 military action in Iraq. 

Two elements of the outcome adopted could mitigate such risks. 

First, under the decision adopted, states parties to the ICC can opt 

out of the ICC’s aggression jurisdiction for cases not referred by the 

U.N. Security Council. If U.S. allies exercised this right, they would 

not incur any greater risk of prosecution for aggression by the ICC 

than would the United States. Second, understandings adopted in 

connection with the definition seek to underscore that aggression 

constitutes only the most serious and dangerous forms of the illegal 

use of force, and applies only when the character, gravity, and 

scale of the illegal use of force is manifest. These understandings 

arguably narrow the circumstances in which the ICC might bring 

an aggression case, and may reduce the likelihood that coalition 

military activities would be considered aggression, particularly 

when undertaken to address threats to civilian populations or to 

regional or international peace and security. 

3. Potential Adverse Development in Law Relating to Use of 

Force—The definition of the crime of aggression adopted by the 

Conference establishes vague standards that would govern important questions relating to the use of military force by states subject 

to the ICC’s aggression regime. As noted by the U.S. delegation in 

Kampala, the definition adopted deviates from existing customary 

international law in a number of respects, and may serve inappropriately to discourage lawful uses of force. Interpretive understandings adopted in connection with the definition serve to mitigate some of its deficiencies, but the definition remains an unsound 

basis for addressing these issues. Were the definition to influence 

the future development of international law outside the context of 

the ICC, future U.S. leaders could face increased criticism in connection with some decisions regarding the use of force, including 

claims that their decisions amount to criminal conduct. 

4. Potential Impact on the U.N. Security Council—The regime 

adopted by the Conference, if made operational and subscribed to 

by a large number of states, would provide the ICC with authority 

to investigate and prosecute cases of aggression without the affirmative approval of the Security Council. In particular cases, the 

ICC’s pursuit of an aggression case against a head of state or other 

senior government official could complicate the Security Council’s 

efforts to address an ongoing threat to peace and security. Accordingly, there is some potential that the proposed aggression regime 

could reduce the effectiveness of the Council’s mechanisms for addressing situations that may be of concern to the United States. 

5. Additional time to work for improvements—Because the aggression regime will not go into effect for at least seven years, the 

United States will have opportunities to further address concerns 

not resolved by the outcome. It could seek greater clarity in the 

definition of aggression, either through changes to the definition or 

11 

the elements of crimes accompanying it, or through further understandings. It will also have the opportunity to consult with allies 

and to develop plans to mitigate risks an ICC aggression regime 

might pose to the ability to plan and carry out coalition military 

operations. 

Implications for the ICC 

1. Potential Politicization—The crime of aggression has a significant political character to it, involving judgments about the legitimacy of decisions by state leaders to use force in situations affecting their security interests. This subjective political aspect of the 

crime is compounded by the vagueness of aspects of the definition 

of aggression. The outcome, if brought into effect, will place the 

ICC Prosecutor at the center of such political questions by giving 

him the mandate to investigate and prosecute aggression on his 

own initiative or at the request of a state. There is a risk that the 

Prosecutor will be drawn into disputes between states, and that the 

Prosecutor’s decisions to pursue—or not pursue—particular cases 

will be seen as taking sides in such disputes. Such perceptions 

could undermine the perceived objectivity and legitimacy of the 

ICC as a judicial institution. 

2. Potential Overstretch—The ICC is currently struggling to carry 

out its current mandate of pursuing cases of genocide, war crimes, 

and crimes against humanity. Eight years after the Rome Statute 

entered into force, the ICC has gained custody of fewer than half 

of the 15 individuals against whom it has brought public charges 

for the core crimes of genocide, war crimes, and crimes against humanity, and it has yet to complete its first trial. Though the ICC 

will have at least 7 years to further build its capacities before an 

aggression regime could take effect, there nonetheless remains the 

risk that adding aggression to the Court’s mandate will divert resources from core tasks and make the ICC less effective as an institution. 

FURTHER OBSERVATIONS ON THE NEGOTIATION PROCESS

In addition to these issues specific to the outcome at Kampala, 

several other developments at the Conference may be of interest to 

the Foreign Relations Committee and to the Senate more generally: 

1. Widespread Dissatisfaction with the U.N. Security Council— 

Much of the discussion at the conference focused on whether the 

ICC Prosecutor should be given the authority to initiate aggression 

investigations and prosecutions independently from the U.N. Security Council. Discussion on this issue in both formal and informal 

settings suggested widespread dissatisfaction with the Security 

Council, particularly among delegations from developing countries. 

These delegations appeared to perceive the Council as an unrepresentative body that does not regularly act in the interests of the 

international community as a whole. For some delegations, pursuing outcomes that appeared to challenge the Security Council’s 

primacy in addressing aggression appeared to be an independent 

objective in the negotiations, separate from the goal of pursuing decisions that would strengthen the ICC or international justice. 

Should such challenges to the Security Council’s role and authority 

12 

become more widespread and arise in other contexts, the Council’s 

effectiveness as an institution could be diminished. 

2. Disparate Views Among NATO Members—While a potential 

ICC aggression regime could impact NATO military operations, 

NATO delegations at the conference were not unified in their substantive views or in their approach to the negotiations. NATO 

members also differed in their views on the importance of giving 

the ICC jurisdiction over aggression at all, with some being vigorous supporters and others skeptical at best. Some NATO delegations were among the chief proponents of an ICC role for aggression independent of the U.N. Security Council, while others felt 

strongly that the ICC should act on aggression only when asked by 

the Security Council. It did not appear from the negotiations that 

NATO members, as a group, had a common understanding about 

the potential implications of various proposals on their operations. 

Because of the relationship of the crime of aggression to decisions 

to use force that are often taken collectively, better NATO coordination on these issues in the future would be prudent. 

3. Effectiveness of U.S. Participation—U.S. participation at the 

conference was well-received, had a significant impact on the outcome and served to protect important U.S. interests. While there 

has been significant past friction between the United States and 

the ICC, and while the Obama administration has made clear that 

it does not support the United States becoming a party to the ICC, 

ICC parties nonetheless are welcoming of increased U.S. engagement with the ICC. Absent U.S. participation and engagement before and during the Kampala Conference, it is unlikely that the 

conference would have specifically exempted non-ICC parties from 

key portions of the proposed aggression regime. It is also unlikely 

that the conference would have adopted understandings to address 

ambiguities in aspects of the definition of aggression. While there 

were limits to the lengths ICC parties were willing to go to address 

U.S. concerns and interests—there was no willingness, for example, 

to consider revising the definition of aggression itself—ICC parties 

did accommodate United States concerns in important respects. 

4. ICC Priorities—The Kampala Conference was the first highlevel meeting of the ICC Assembly of States Parties since the Rome 

Statute was adopted in 1998. It is notable that the parties were 

concerned primarily with expanding the ICC’s jurisdiction to cover 

an additional crime rather than with considering ways of improving its ability to address effectively the crimes currently in the 

Court’s mandate. The Conference gave only passing consideration 

to important practical obstacles currently faced by the ICC, including securing cooperation from states with ICC orders, gaining custody of persons charged with crimes, protecting victims and witnesses, facilitating evidence sharing and other legal assistance 

from states, and improving the efficiency of trial proceedings. The 

choice by the ICC parties to focus on aggression rather than on developing solutions to these challenges suggests that the parties 

were more concerned with the symbol of adopting an aggression regime than with the substance of building an effective institution. 

Absent greater focus on addressing these operational difficulties, 

the ICC may continue to struggle in carrying out its basic judicial 

functions. 

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ANNEX—ICC REVIEW CONFERENCE DECISION ON AGGRESSION


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