Grassroots organizing and collective action have always been fundamental to American democracy but have been burgeoning since the 2016 election, as people struggle to make their voices heard in this moment of societal upheaval. Unfortunately much of that action has not had the kind of impact participants might want, especially among movements representing the poor and marginalized who often have the most at stake when it comes to rights and equality. Yet, some instances of collective action have succeeded. What’s the difference between a movement that wins victories for its constituents, and one that fails? What are the factors that make collective action powerful?