An international Court.
But, as Atlanta knew very well, Chalakanesia was negotiating with Heaven and Hell on the text of a proposed International Justice Treaty. This would enshrine a number of human rights, such as freedom from judicial caprice, and protection against retrospective legislation. Furthermore, it would allow Chalakanesians to go to the international Court of Conference to seek remedies for any Breach of Treaty.
Heaven and Hell wanted such a treaty because they expected that technological advances would soon allow their airships to fly to Chalakanesian territory. This would vastly increase the commercial intercourse between Chalakanesia and the Great Powers, so Heaven and Hell wanted legal guarantees which would protect the Big Money of the Great Powers when that Big Money went to work in Chalakanesia. [WoH Ch10]