Farmer–herder conflicts in Africa are often presented as being driven by ‘environmental scarcity’. Political ecologists, however, argue that these conflicts should be analysed within a broader historical and policy context. This article presents a case study of a local conflict in the Kilosa District in Tanzania that tragically culminated in the killing of thirty-eight farmers on 8 December 2000. To understand the conflict, the authors argue that it is necessary to study the history of villagization and land use in the District, as well as national land tenure and pastoral policies. Attempts at agricultural modernization have fostered an anti-pastoral environment in Tanzania. The government aim is to confine livestock keeping to ‘pastoral villages’, but these villages lack sufficient pastures and water supplies, leading herders to search for such resources elsewhere. Pastoral access to wetlands is decreasing due to expansion of cultivated areas and the promotion of agriculture. The main tool that pastoralists still possess to counteract this trend is their ability to bribe officials. But corruption further undermines people's trust in authorities and in the willingness of these authorities to prevent conflicts. This leads actors to try to solve problems through other means, notably violence.