This is a good time for serious discussion about the international law crime of aggression, and this is a good book to begin it. After a deceptively false start at Nuremberg, and a tentative definition in 1974 endorsed by a General Assembly Resolution, it appeared elliptically in Article 5 of the Rome Statue a quartercentury later as a crime within the jurisdiction of the International Criminal Court, but a jurisdiction which would be suspended until an up-to-date definition could be agreed. Agreement was not reached until the Kampala Review conference in 2010, and thus potential liability for the commission of aggression went unmentioned in the debates over the Bush/Blair invasion of Iraq without Security Council approval in 2003. The Kampala Amendments required a minimum of thirty ratifications, and the new State of Palestine lodged the thirtieth in 2016, Crimea having been “annexed” in the meantime. That left a further year before activation of the jurisdiction by a two-thirds majority of State Parties, which happened on December 14th, 2017, after a bitter fight over its scope in the Assembly of States Parties.

In the result, the crime will be punishable if committed after 17th July 2018, but not by nationals of a non-ratifying State or on such a State's territory (although these cases should still be referable to the ICC by the Security Council). In the meantime, there has been the attack on a Syrian airbase ordered by President Trump, avowedly to punish President Assad for his likely (although not forensically proven) use of chemical weapons against civilians. This set the academic dovecotes fluttering: was it a blatant breach of the U.N. Charter, or justified as some form of humanitarian intervention, or by a derivative of Responsible to Protect (R2P), or a contorted version of self-defense? As mutterings are still coming from the White House about a possible attack on North Korea, it is time to contemplate the consequences – in this case through illuminating essays of experts who were assembled at an important conference at Washington University in St. Louis School of Law in 2015.