Full Idea
Leibniz rejects Hobbes's legal positivism in favour of the older natural law theory associated with Aquinas (which says nothing can be a law unless it derives from natural justice). The older view was revived at Nuremberg, to prosecute Nazis.
Gist of Idea
Natural law theory is found in Aquinas, in Leibniz, and at the Nuremberg trials
Source
report of Gottfried Leibniz (works [1690]) by Nicholas Jolley - Leibniz Ch.7
Book Reference
Jolley,Nicholas: 'Leibniz' [Routledge 2005], p.195
A Reaction
This seems to suggest that Hobbes and co were using Ockham's Razor to eliminate morality from the law, but that the Nuremberg situation (and modern trials in The Hague) show that there is a necessity for natural law in international situations.