Alberto Simser and Daniela Donno have posted an abstract of a Journal of Politics paper which looks very, very interesting:

The monitoring of elections by international groups has become widespread. But can it have unintended negative consequences for governance? We argue that high-quality election monitoring, by preventing certain forms of manipulation such as stuffing ballot boxes, can unwittingly induce incumbents to resort to tactics of election manipulation that are more damaging to domestic institutions, governance and freedoms. These tactics include rigging courts and administrative bodies, and repressing the media. We use an original panel dataset of 144 countries in 1990-2007 to test our argument. We find that, on average, high-quality election monitoring has a measurably negative effect on the rule of law, administrative performance and media freedom. We employ various strategies to guard against endogeneity, including instrumenting for election monitoring.