Collective Action Problem
A Collective Action Problem arises when all individuals in a group would benefit from cooperation, but each individual has a rational incentive to free-ride on others' contributions. The result is systematic under-provision of public goods and over-exploitation of shared resources. Documented in Mancur Olson's *The Logic of Collective Action* (1965), it explains why unions struggle, environmental protections fail, and international agreements collapse β and how they succeed when they do.