Books by John Prendergast On June 7, yet another round of negotiations between officials from Sudan and South Sudan broke up without the conclusion of any concrete and sustainable agreements. This last round of talks centered, in large part, on discussions of the ill-defined international border that divides the two countries and related security issues. On June 7, yet another round of negotiations between officials from Sudan and South Sudan broke up without the conclusion of any concrete and sustainable agreements. This last round of talks centered, in large part, on discussions of the ill-defined international border that divides the two countries and related security issues. The discussions took place within the context of the Joint Political and Security Mechanism, or JPSM, a bilateral implementation mechanism established in December 2010 by agreement of the two parties and composed of military, security, police, and government officials from both Sudan and South Sudan. The definition of the so-called Safe Demilitarized Border Zone, or SDBZ, was a major dispute between the two parties.