International efforts to promote democracy can have unanticipated effects. International election observation is perceived to increase domestic confidence in the electoral process and reduce fraud. Conversely, election boycotts are perceived to be more likely as electoral fairness decreases. We document a puzzling relationship between monitored elections and opposition party boycotts: observers are associated with an increased probability of a boycott. We argue that international benefits for democratic elections give electoral autocrats the incentive to invite international observers and manipulate elections such that international criticism is minimized. This increase in "strategic manipulation" has, in turn, led to changed incentives for opposition political parties who have the most to lose from a manipulated but internationally certified election. Consequently, international monitors increase the probability of a boycott. We support this explanation with an original dataset of elections, boycotts, and international observers, 1990-2002...