While previous studies show that conflict is less likely to recur if implementation of an agreement is successful, little work has focused on identifying the factors that lead to successful implementation. In other words, following a negotiated settlement of a civil war, what causes warring parties to fulfill their promises of implementing reforms in different issue areas instead of reneging or returning to violence? Similarly, why are some peace agreements fully implemented while others are only partially or never implemented? Additionally, while successful implementation is a necessary condition for durable peace, not all partial or failed implementation cases lead to conflict recurrence. Therefore, a subsequent question raises, why do some partial and failed implementation processes lead to conflict recurrence while others do not? This dissertation addresses these questions in a two-step process. In the first part, this dissertation identifies the conditions under which state- and non-state actors would be more inclined to fulfill or evade their responsibilities deriving from particular agreements. The second part focuses at variation in the degree of implementation and its effect on post-conflict outcomes, mainly conflict recurrence.

Building upon the bargaining theory of war, this dissertation argues that bargaining between parties does not stop once an agreement is signed. The implementation of an agreement is a continuation of the bargaining process in which both sides try to get the maximum amount of concessions they can while updating their beliefs on the gains and losses to be made by staying in the peace process or abandoning it. Therefore, the negotiation and implementation stage should both be taken into account to fully understand successful transitions to peace, and the incentive of parties to continue implementation. The main argument is that as long as the costs of non-compliance remain high, both parties will continue implementation. Both sides, but especially non-state actors, should retain their military capability to enforce the implementation of the agreement and credibly threaten renewed violence in the wake of failed implementation. A series of statistical models using original dataset on the implementation of peace agreements provides support for this theory.