In New Delhi, the leaders of a coalition that has grown from four nations to nearly twenty gathered to mark two decades of an experiment in collective ambition — the attempt by the Global South to build a voice of its own. BRICS has succeeded in attracting members and commanding attention, but the deeper question it now faces is whether size and solidarity are the same thing. History suggests that coalitions are easy to expand and difficult to govern, and the tensions surfacing in New Delhi are less a crisis than a reckoning with that ancient truth.