Zohran Mamdani’s tenure as New York City mayor has raised hopes of a more invigorated, deeper form of democracy and posed a question facing progressive mayors everywhere: how to translate the grassroots energy that brings them to office into a sustained movement for change. In our new book, The Power and Perils of Participatory Democracy: Participatory Budgeting and Democracy in Peru, we provide several answers to that question while tempering both naive optimism and unnecessary cynicism.

Peru, as we document, might be “the most participatory place on earth.” Since the return of democracy in the early 2000s, the country has built thousands of participatory institutions at the local and regional levels, engaging ordinary citizens in decisions ranging from infrastructure spending to urban planning — not just a few exemplary cities here and there but a nationally mandated system across thousands of municipalities. We have spent two decades studying it.

Our central finding will both hearten and humble today’s progressive mayors: participatory democracy works, but not in the way its most ambitious advocates have hoped.