After 13 years of fighting two counter-insurgency wars, the United States is entering another interwar period, and its Army must now justify its value and relevance at a time when the “biggest threat to U.S. national security” appears to be a run-away budget deficit. This Strategic Research Paper first identifies those lessons learned during previous interwar periods that are useful to Army leaders of today as they contemplate transformation in the 21st century. It then compares different arguments for how the emerging Army of the 2020’s should re-organize. This paper advocates for a consolidation of existing army structure, a reorganization of its capabilities, and a transformation of its role in the joint force supporting U.S. national security interests. In sum, it offers a plan for best managing the Army’s restructuring to a smaller, yet lethal, force while ensuring relevancy to the security environment of this interwar period and meeting the goals outlined in the 2014 Quadrennial Defense Review. In the end, it will advocate for a 380K army that is optimized on the “left end” of conflict while preserving “at-risk” armor capability and a strategic vision characterized by a pivot to everywhere the rest of the Joint Force is not.