Blog | The Crime of Aggression: How to Stop a War (or at Least Make Politicians Think Twice)

Blog | The Crime of Aggression: How to Stop a War (or at Least Make Politicians Think Twice)

By Nancy Chen

The Crime of Aggression

In the context of international law, “aggression” refers to state conduct that either initiates war directly or drives another state to war. The Crime of Aggression makes an individual liable for an act of aggression committed by a state. As such, state actors (e.g., political and military leaders) who order the invasion of a foreign country may be guilty of the Crime of Aggression under the Rome Statute and punishable at the International Criminal Court in the Hague. This is a direct result of the 2010 Kampala Amendment.[1]

The Rome Statute entered into force in 2002, with the Crime of Aggression incorporated into the Statute during the 2010 Review Conference in Kampala. The definition of “aggression”, as decided by the United Nations General Assembly, exists in the sphere of international criminal law. Article 5 of the Rome Statute gives the International Criminal Court jurisdiction when it comes to genocide, crimes against humanity, war crimes and the Crime of Aggression. Following that, a new clause (Article 16 bis) was inserted into the Rome Statute in Kampala which proclaimed that “[t]he Court may exercise jurisdiction only with respect to Crimes of Aggression committed one year after the ratification or acceptance of the amendments by thirty State Parties”. This established a minimum number of 30 ratifications as a condition necessary for the activation of the Court’s jurisdiction over the Crime of Aggression. This criterion has been met.

Those who direct the use of armed force against the “sovereignty, territorial integrity or political independence” of another member state in a manner which “by its character, gravity and scale” amounts to a “manifest violation” of the U.N. Charter are liable to the Crime of Aggression. The new offence cannot, however, be enforced retrospectively over conflicts such as the 2003 Iraq invasion.


Who does it affect?

Although the International Criminal Court’s power to prosecute under the Rome Statute has been activated since 17th July, its direct reach only applies to nationals of countries that have ratified the newly defined crime. However, individual state actors from countries that have not ratified the amendment may still be charged through a reference by the U.N. Security Council to the International Criminal Court (ICC).

Despite the independence in ruling on matters of jurisdiction for ICC judges, and the referrals from the U.N. Security Council having no limits, in practice the Crime of Aggression is still limited. Countries such as Britain, the United States and Russia have the power of veto. Hypothetically, a politician or military leader in the crosshairs of the Crime of Aggression may be protected through veto if they act in alliance with one of the U.N. Security Council’s “big five”.[2]

As of now, a total of 35 nations have ratified the Kampala amendment. Most of them are European — such as Germany, Spain, Switzerland, and the Netherlands — while no Asian countries have signed on.[3]

For the countries that have ratified, leaders who commit Aggression through the use of armed force will become individually liable for conviction in their domestic courts or in the Hague.[4] New Zealand is not among this first group, but it can join them at any time by a constitutional act of ratification.

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Applicability in New Zealand?

In 2012, Former Green Party MP and current Director of the New Zealand Centre for Global Studies Kennedy Graham put forward a private member’s bill in an attempt to push for New Zealand to sign up and help ratify the Kampala amendment.[5] A 2013 Foreign Affairs, Defence and Trade Select Committee report[6] recommended the government give priority to New Zealand becoming one of the 30 founding states needed to implement it.[7] However, in both instances it was never moved forward. Following the recent activation of the amendment in July, the debate surrounding the Kampala amendment has reignited.

At a seminar in Wellington following the activation, Justice Minister Andrew Little confirmed that New Zealand has been looking to ratify. “The work is underway”, he said, stating that the process would require further advice in order to reconcile it with New Zealand’s domestic procedures.[8]

Winston Peters has noted that “New Zealand supported the inclusion of the Crime of Aggression in the Rome Statute when it was negotiated in 1998 and actively participated in the Review Conference in Kampala in 2010”. “New Zealand is not able to ratify the Crime of Aggression amendments without first putting new legislation in place.”[9] In particular, this would involve amendments to our International Crimes and International Criminal Court Act 2000.


The case for New Zealand supporting the decision to make waging aggressive war a crime was summed up by Former Prime Minister, Sir Geoffrey Palmer. “As a small nation like New Zealand, we have to be in favour of progress at international law”. Palmer said New Zealand had a long tradition of supporting the international rule of law.[10]

The implementation of the Rome Statute’s amendments in New Zealand would have two key effects. For one, it would ensure that the use of armed force by state actors in New Zealand conforms with international law, as well as protect New Zealand leaders from external international pressures. Secondly, it would ensure that no leader of another state uses armed force against New Zealand with impunity, as such action would become a criminal offence in New Zealand law. In saying this, New Zealand (or any other state) maintains the ability to use armed force when exercising the inherent right of individual or collective self-defence under the U.N. Charter.

Concerns surrounding the activation of the ICC’s jurisdiction over the crime of aggression point to the limiting effect it may have on military actions (such as humanitarian interventions) that may lack legal authorisation by the U.N. Security Council or fall outside the right to self-defence. While this concern is understandable, before such action becomes liable under the Rome Statute it must satisfy the “character, gravity, and scale” requirement under the U.N. Charter. This infers that legitimate humanitarian intervention or action with humanitarian objectives in mind is beyond the scope of the Crime of Aggression, in the same way that the defence of necessity is accepted in certain criminal law cases.


There are numerous legal complexities surrounding the application of the Rome Statute and the following Kampala amendments that will challenge both lawyers and policy-makers for decades ahead. It is the nature of contemporary international relations to be extremely sensitive to issues that fall within the overlap of politics, law and military action.

New Zealand has no reason to delay ratification of the Kampala Amendment. Ratification would show New Zealand to be a principled member of the international community, and reflect its obligation under the UN Charter not to commit acts of international aggression.



[2] China, France, Russia, the United Kingdom and the United States are considered the “big five” due to their status as a permanent member of the U.N. Security Council.











The Public Policy Club is a non-partisan club at the University of Auckland that aims to encourage, educate and involve students from all backgrounds in the education and development of political knowledge. The views and opinions expressed in this article are those of the author and do not necessarily reflect those of PPC.

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