The past few years have witnessed the rise of anti-globalization sentiments in which certain treaties have succumbed to domestic political backlash. But why are particular treaties susceptible to breakdown while others tend to be more resilient? Paradoxically, this Article argues that the fragility of treaties follows a peculiar logic: treaties are most vulnerable to breakdown or withdrawal if they were originally negotiated in the absence of social conflict among domestic groups. The reason is that having been negotiated and ratified with hardly any political struggle, consensus treaties often lack the support of battle-hardened special interest groups who are willing and able to defend such treaties against downstream political threats. This Article uses the contemporary backlash against both bilateral investment treaties and the Rome Treaty establishing the International Criminal Court to illustrate the vulnerability of consensus treaties. By contrast, treaties negotiated amidst intense political disagreement, such as the GATT/WTO framework governing international trade, have exhibited remarkable resilience over time. On a more speculative note, both the Trans-Pacific Partnership (TPP) and the Transatlantic Trade and Investment Partnership (TTIP) were likely rendered politically fragile by the first generation of consensus investment treaties entered into by the United States. Finally, it concludes by recommending measures to counteract the tendency of consensus treaties to collapse by making them more politically sustainable.