The ICC Appeals Chamber, in a unanimous decision it described as “unprecedented”, has confirmed that the rape and sexual slavery of children by members the same armed group can be charged as war crimes under the Rome Statute.

The decision came in the case against Bosco Ntaganda, alleged former deputy chief of the staff of the Forces Patriotiques pour la Libération du Congo (FPLC).

The FPLC, one of the armed groups involved in the 2002-2003 conflict in Ituri, Democratic Republic of Congo, was also the focus of the ICC’s first trial, against convicted war criminal Thomas Lubanga Dyilo.

In that case, the (then) ICC Prosecutor was widely criticised for not bringing charges for the reported sexual abuse of children who had been unlawfully recruited by the FPLC – children that the ICC Office of the Prosecutor, and the ICC judges, refer to as “child soldiers”.

The prosecution later brought evidence of this sexual abuse in Lubanga’s trial. But because the prosecution had not referred to this evidence when it applied for confirmation of the charges, the majority of the Trial Chamber refused to determine Lubanga’s criminal responsibility for these crimes.

The Ntaganda case presented a chance to get a different result.

In this case, the prosecution got off to a better start by including charges for the sexual abuse of the FPLC “child soldiers” at the pre-trial stage. It charged this abuse using the war crimes of rape and sexual slavery, under Article 8(2)(e)(vi) of the Rome Statute.

These charges were challenged by the Defence, who argued that war crimes must involve a violation of international humanitarian law (IHL), and IHL does not protect persons taking part in hostilities from acts of sexual violence perpetrated by members of the same armed group.

In other words, it is not a war crime if the victim and the perpetrator were part of the same armed group.

For this reason, the Defence argued that the alleged sexual abuse of the FPLC “child soldiers”, even if proved in court, would not amount to war crimes within the jurisdiction of the ICC.

On 14 June 2014 – almost three years ago to the day – the Pre-Trial Chamber confirmed the charges in question. As a result, Ntaganda became first person in the ICC to face charges for sexual violence crimes committed both by and against members of the same armed group.

On 4 January 2017, after further challenges from the Defence, the Trial Chamber decided that it did have jurisdiction over these sexual violence charges. The Defence appealed. Today’s Appeals Chamber decision put an end to this dispute.

Judge Sanji Mmasenono Monageng, Presiding Judge of the Appeals Chamber, delivered the summary of the decision. There will be lots more to say when the full decision becomes available, but in the mean time, here are some key points.

The Appeals Chamber upheld the Trial Chamber’s decision, meaning that the charges of rape and sexual slavery against the FLPC “child soldiers” will not be dropped.

It found that the established framework of international law does not impose “status requirements” for the war crimes of rape and sexual slavery, meaning that the victims and perpetrators of these crimes can be members of the same armed group.

The Chamber did not seem to see this outcome as dependent on the age of the victims, which suggests that the war crimes of rape and sexual slavery could potentially be prosecuted even if the victims were over 15.

It acknowledged the Defence’s concerns of “judicial activism”, and its protests against an overly broad interpretation of the crimes. However, the Chamber pointed out that ICC’s definition of war crimes requires that the sexual abuse “took place in the context of and was associated with” an armed conflict. In the Chamber’s view, this definitional requirement is enough to prevent an unduly broad interpretation of the war crimes of rape and sexual slavery.

It is a sign of the gender blindness of IHL and ICL that until now, it was not clear whether the sexual abuse of children by members of their “own” armed group can, in fact, be a war crime.

By answering that question in the affirmative, the ICC Appeals Chamber has made an enormously important contribution to international criminal law.