The phrase multi-domain has reached beyond mainstream military parlance to dominate defense-related discussions, concept papers, and op-eds. While the idea of operating across warfighting domains is hardly original, the rapid growth of capabilities tied to the newly minted cyber and space domains is forcing a reexamination of all previous military concepts and doctrine. This paper explores the concept debate around multi-domain battle (MDB) and makes an argument for supplementing Service-centric experimentation with a joint/theater level experimental campaign.