A proxy war is a conflict in which one party fights its adversary via another party rather than engaging that party in direct conflict. This article discusses two examples: the Sudan-Ugandan proxy war of the 1990s and the Sudan-Chad proxy war that has fed the conflict in Darfur. In these cases, the states aimed to alter regional power structures through cross-border rebel support. This support generated a perpetual Prisoners’ Dilemma whereby the patron governments refused to end proxy support unless the other side did as well, but had little reason to trust that the other side would do so. The Sudan-Uganda and Sudan-Chad peace processes succeeded in reaching agreement, but failed in implementation. Permanent resolution of such complex, persistent, and deadly conflicts requires conflict analyses that take a regional view; conflict mediation that seeks to alter the underlying conflict dynamics through addressing the motivations of both patrons and proxies; and implementation agreements backed by strong guarantees.