Abstract: Activists play a key role in the process of democratic transition and consolidation. How is their activism affected by democratic reforms? We study how local activism in England and Wales responded to the changes in representation introduced by the Great Reform Act of 1832. This reform reduced parliamentary representation in some areas and increased it in others. We exploit exogenous variation in which areas lost and gained representation and measure activism using the number of petitions each area sent to parliament. We find that petitioning increased in areas that gained representation, partly because of greater civil society mobilization, while petitioning fell in areas that lost representation. This shows that pro-democratic reforms can promote political activism, while anti-democratic reforms can decrease it. In the specific case of England and Wales, positive feedback between activism and reform helped make democratization a path-dependent process with the Great Reform Act its critical juncture.