National secession seeks to create a new sovereign state for a nation residing on its homeland that is currently located inside another sovereign state. This goal distinguishes national secession from regional secession, autonomy, and decolonization and shapes the strategies, operational objectives, and tactical choices of the leaders of national-secession campaigns. Explanations for the success of some campaigns—particularly, success at getting on the global agenda—have focused on the identities, grievances, or greed of their members. Explanations for why some campaigns have turned to protracted intense violence have focused on these motivations and on tactical-logistical opportunities. The existing literature suffers from its failure to agree on theoretical and conceptual fundamentals. As a consequence, empirical studies focus on very different universes of cases and operationalize key variables in diverging ways. The existing literature frequently does not consider how the goal of national secession constrains the strategies, operations, and tactics of such campaigns. And so, it often fails to consider whether studies with another dependent variable can be extended to the study of national secession. Explanations stress indeterminate or substitutable causes and remote constraints on most national-secession campaigns—causes and constraints taken “off the shelf” from theories about conflicts operating under very different strategic and operational constraints. Missing from these explanations is the authenticity and realism of the programs for national secession in the assessments of the populations that each program presents as a nation with a right to a sovereign state of its own. Explanations and recommendations for responses by common-state governments, their allies, and the international community often fail to understand the centrality of the war of programs between national secessionists and common-state governments and the ways this constrains what compromises are possible and what responses are most likely to lead to domestic and international peace in such conflicts.