Why do some states withdraw from international regimes? How do others successfully renegotiate the terms of international cooperation? This thesis investigates whether, and how, the changing bargaining power relations impact treaty-based cooperation in the international investment treaty regime. The institutional architecture to govern investments consists of a web of bilateral investment treaties (BITs). The investor-state dispute settlement (ISDS) mechanism embedded in most BITs has resulted in an accumulation of arbitration cases between host governments and foreign investors, and states have increasingly begun to question their investment treaties. I argue that while states have learned about the true risks of investment treaties through ISDS, they must have sufficient bargaining power to act in response. Bargaining power is best understood as alternatives to the existing agreements. Alternative economic treaties and domestic investment laws facilitate foreign investment and decrease dependency on the existing agreements. Economic improvement can also bring confidence for a government that such alternatives can be developed. When sufficient alternatives are in place, a state can either exit the agreement, demand renegotiation, or conduct a strategic exit with intentions to renegotiate at a later stage. The optimal strategy for a revisionist state depends on the bilateral relationship between the states, and how important they consider their partnership. I employ a mixed methods approach to provide evidence for my argument. I use data on bilateral investment treaties to show that bargaining power is associated with greater risk of BIT termination and renegotiation. Relative changes in economic power also condition the effects of ISDS on BIT outcomes. Interviews conducted with Ecuadorian and Indonesian policymakers show that governments are strategic in reflecting on their outside options when considering BIT reform. By examining the dynamics of investment treaty reform, this thesis contributes to a better understanding of change in international regimes governing the world economy.