This book has a powerful and timely message, though one weakened by overstatement. At its core is the Pact of Paris signed on 27 August 1928, better known as the Kellogg-Briand Pact (named after the then American secretary of state and the French minister for foreign affairs). The document’s text is simple:

Article I: The High Contracting Parties solemnly declare in the names of their respective peoples that they condemn recourse to war for the solution of international controversies, and renounce it, as an instrument of national policy in their relations with one another.
Article II: The High Contracting Parties agree that the settlement or solution of all disputes or conflicts of whatever nature or of whatever origin they may be, which may arise among them, shall never be sought except by pacific means.

In short, the pact aspired to outlaw war. Oona Hathaway and Scott Shapiro, both professors at Yale Law School, claim its signature was ‘among the most transformative events of human history’. They acknowledge that this assertion is, to put it mildly, counterintuitive. Most of the standard texts on the modern history of international relations give the Kellogg-Briand Pact only the briefest of mentions; commentators from George Kennan to Henry Kissinger have been derisive. Of the pact’s fifteen original signatory states (the number has since risen to sixty-seven, including Bosnia and Herzegovina as recently as 1994), all but Ireland participated in the Second World War little more than a decade later, and the world in 2017 seems to show few signs of being emancipated from armed conflict. 

Undismayed, the authors argue persuasively for a reappraisal. Their approach is initially narrative as they describe the ‘Old World Order’ that preceded 1928, but becomes more analytical as they discuss the ‘New World Order’ that since the Kellogg-Briand Pact – or, in practice, since the founding of the United Nations