With the rise of right-wing political parties in many countries, the question of how to organize democratically and effectively has become increasingly urgent. Although today's leaderless political organizations are not sufficient, a return to traditional, centralized forms of political leadership is neither desirable nor possible. Instead, as Michael Hardt and Antonio Negri argue, familiar roles must be reversed: leaders should be responsible for short-term, tactical action, but it is the multitude that must drive strategy. In other words, if these new social movements are to achieve meaningful revolution, they must invent effective modes of assembly and decision-making structures that rely on the broadest democratic base. Drawing on ideas developed through their well-known Empire trilogy, Hardt and Negri have produced, in Assembly, a timely proposal for how current large-scale horizontal movements can develop the capacities for political strategy and decision-making to effect lasting and democratic change. We have not yet seen what is possible when the multitude assembles.