This paper examines the effects of the abandonment of China's Grand Canal—the world's largest and oldest artificial waterway—which served as a disruption to regional trade access. Using an original dataset covering 575 counties over 262 years, we show that the canal's abandonment contributed to the social turmoil that engulfed North China in the nineteenth century. Counties along the canal experienced an additional 117 percent increase in rebelliousness after the canal's closure relative to their non-canal counterparts. Our findings highlight the important role that continued access to trade routes plays in reducing conflict.

Does physical surveillance hinder or foster antiregime resistance? A common view holds that surveillance prevents resistance by providing regimes with high-quality intelligence on dissident networks and by instilling fear in citizens. We contrast this view using formerly classified data from Communist Poland. We find that communities exposed to secret police officers were more likely to organize protests but also engaged in less sabotage. To ensure that the relationship is causal, we use an instrumental variable strategy, which exploits the exogenous assignment of Catholic “spy priests” to local communities. To trace the underlying mechanisms, we draw on qualitative interviews and archival sources. We document that Poland’s comprehensive use of surveillance created widespread anger as well as an incentive for citizens to reveal their true loyalties, thus facilitating antiregime collective action. Once on the streets, protesters refrained from sabotage to signal their political motivation to bystanders and authorities alike.