Governments allocate property rights in different ways to protect common-pool resources (CPR) from over-harvesting, but this can generate conflict between those with access (``insiders'') and those without (``outsiders''). We use a laboratory experiment to determine how mechanisms to allocate property rights influence the decentralized management and defense of a CPR. We use a 2x2 design that varies whether access to the CPR is earned (as opposed to being randomly assigned) and whether insiders have the ability to use punishment to deter outsiders from poaching the resource. We find that insiders who earned the property right were more likely to defend the CPR and impose significantly more deterrence, leading to a significant reduction in extreme poaching. However, lower levels of poaching often went unpunished under both earned and assigned rights. While earned property rights can improve the coordinated deterrence of outsiders, they are insufficient to completely eliminate poaching, and conflict between rights-holders and poachers.