** **Conditionally accepted, Review of Economic Studies** ** Diversity can pose fundamental challenges to state-building and development. The Tanzanian Ujamaa policy — one of post-colonial Africa’s largest state-building experiments — addressed these challenges by resettling a diverse population in planned villages, where children received political education. We combine differences in exposure to Ujamaa across space and age to identify long-term impacts of the policy. Analysis of contemporary surveys shows persistent, positive effects on national identity and state legitimacy. Exposed cohorts are also more likely to marry across ethnic lines. Our preferred interpretation, supported by evidence that considers alternative hypotheses, is that changes to educational content drive our results. Our findings also point to trade-offs associated with state-building: while the policy contributed to establishing the new state as a legitimate central authority, simultaneously it lowered demands for democratic accountability. *[[NBER working paper]](https://www.nber.org/system/files/working_papers/w30731/w30731.pdf/)* [[pdf]](https://www.jorismueller.com/files/statebuilding_Ujamaa_latest_draft.pdf/)
** **AEA Papers & Proceedings Vol. 114, May 2024** ** This study uses historical conflict and weather data for the period 1400–1900 CE to investigate the long-run effects of climate change on political instability in a context that suffered extensive cooling. The results show that temperature changes have little effect on conflict if they are isolated events but that consecutive periods of cooling are associated with increased conflict. This is consistent with the conventional wisdom that societies and economies are able to adapt to a certain amount of environmental change. But if climate change is prolonged, then the disruptions they cause can cumulate and lead to political instability. [[pdf]](https://www.aeaweb.org/articles?id=10.1257/pandp.20241058)