Any significant homeland response event requires Americans to work together. This is a complex challenge. The authors assert that the principal obstacle to effective homeland response is a recurring failure to achieve unity of effort across a diverse and often chaotic mix of participating federal, state, and local government and nongovernmental organizations. Despite a decade of planning since the terror attacks of September 2001, unity of effort still eludes us-particularly in the largest and most dangerous of crises. The authors examine how the military's joint doctrine system affected joint military operational capabilities, concluding that a similar national homeland response doctrinal system is needed to create and sustain unity of effort. Doctrine performs a vital unifying function in complex operations, standardizing ways and means.