Missouri’s application for statehood was immediately and universally recognized as a moment of crisis for the Union. The resolution of the crisis would come in the form of a compromise that came to structure antebellum responses to intersectional conflict over slavery until its collapse in the Civil War. But in moving toward this compromise, these congressional debates generated important components of a constitutional imaginary that would be invoked to navigate constitutional debates over slavery in the following decades. Three elements are evident in the congressional debates over Missouri’s admission that provided building blocks for future constitutional development; the notion of a chronological gap between an authoritative founding and the contemporary moment, the idea of compromise, and the deployment of a founding spirit as a basis for deriving constitutional meaning. This chapter traces the complex interactions of these elements within the Missouri debates, showing that while they failed to consolidate into a singular constitutional imaginary they provided the context within which the history discussed in the following chapters unfolded.