Opinio Juris was the world’s first blog dedicated to the informed discussion of international law by and among academics, practitioners and legal experts. The blog was founded in 2005 by three legal scholars: Chris Borgen (St. John’s University); Peggy McGuinness (St. John’s University); and Julian Ku (Hofstra). Kevin Jon Heller (University of Copenhagen/ANU) joined the following year. The contributors aim to describe and analyse international law where it is most controversial and ambiguous.

On an average day, Opinio Juris is read by more than 3,000 people in 70+ countries. Posts have been cited by international and domestic courts, international arbitrators, and government officials. Opinio Juris posts have also been cited thousands of times in academic and professional publications.  In 2007, the Legal Advisor to the State Department, John Bellinger III, guest-blogged at Opinio Juris – the first time a US government official blogged in an official capacity on international law. 

In 2018, Opinio Juris underwent its most significant restructuring, with Julian and Kevin assuming day-to-day responsibility for the blog and the other members – Chris; Peggy;  Roger Alford (Notre Dame); Duncan Hollis (Temple); Peter Spiro (Temple); Kristen Boon (Seton Hall); Deborah Pearlstein (Cardozo); and Jens Ohlin (Cornell) – taking Emeritus status. 

At the same time, the blog also announced a new partnership with the International Commission of Jurists, founded in 1952, which brings together senior judges, lawyers, and legal academics representing the world’s many legal systems to promote and protect the rule of law. The ICJ’s International Secretariat is based in Geneva and operates on all continents to develop and implement international and regional human rights law, to protect the independence of judges and lawyers, and to provide accountability for violations.

Each author of a post on Opinio Juris will decide whether to permit comments, and all comments will be moderated before appearing on the blog. Abusive and defamatory comments or hate speech will not be tolerated, and users who persistently disregard the blog’s policy will be blocked from commenting further.

This site is not intended to convey legal advice. All contributors post or record Fresh Squeezed Podcast episodes in their individual capacity, and their opinions do not necessarily reflect the official position of Opinio Juris, the ICJ, or any organisation with which the author is affiliated.