THE first review conference of the international criminal court (ICC) begins on Tuesday (June 1) in Kampala, Uganda, and there will be a new face in the room. Although the US has not signed up to the Rome statute - the treaty that created the court - it will, for the first time, join the discussions as an interested observer.

Just how significant a signal this is from the Americans, as an indicator of the possibility of membership in the future, remains in dispute.

The US ambassador for war crimes, Stephen Rapp, is symbolic of the US position. Rapp is no stranger to international criminal justice as the former chief prosecutor at the Sierra Leone special court - a position which he used to heal some of the rifts caused by his predecessor, David Crane.

Rapp is in Kampala hoping, he has said, “to catalyse and assist in broader efforts of societies ravaged by violence to strengthen their own systems of protection and accountability” and “to examine ways that the United States might be able to support the efforts of the ICC already under way”.

I met Rapp in London and he was careful not to give anything more away about the US position on the ICC. It is well known, however, that one of the issues that will provide a sticking point for US membership is the crime of aggression, which some states want included in the court's jurisdiction. The Americans oppose any prosecutions for the crime of aggression - with state department legal adviser Harold Koh saying it “could divert the ICC from its core mission and politicise this young institution”.

US membership is a crucial issue for the ICC but not the only one. Questions remain about the chief prosecutor, Luis Moreno-Ocampo, who has been under fire for years over his handling of the court's caseload and its staff. At last year's Hay festival he said that ICC members including the UK were not doing enough to ensure the arrest of the Sudanese president, Omar al-Bashir, for war crimes and crimes against humanity.

— The Guardian, London