The Army’s civilian and military senior leaders traditionally have two distinct roles: a strategic role as key military advisors in the development of national and warfighting strategy— including resourcing—and an institutional role as designers, organizers, trainers and equippers of the Army. The most successful leaders have generally weighted efforts to the institutional role while metering efforts to change strategies and budgets. We will show that leaders who focused on leading the internal change required in the Army were more successful not only at mitigating the effects of directed strategic change but also at alleviating the inevitable gaps created between strategy and resources that have occurred in every drawdown period since the end of the Spanish–American War in 1898. On the other hand, we will demonstrate that the most energetic attempts to influence strategic policy and resourcing of the Army during a down period had only marginal success and caused the Army to get its initial dispositions wrong for the first battle of the next war.Army leaders must prepare for two categories of change. The first is externally directed change in national strategy, policy, law, regulations and budgets that emanates from the President, the Secretary of Defense or Congress. The second category is internal change made in response to evolving threats, technology or changes to environmental variables, such as political, military, economic and social information; infrastructure; physical environment; and time. A historical review of Army adaptation follows that describes the major periods of change and identifies the strategic directed and internal institutional lessons from each period. This review demonstrates that successful Army leaders use strategic debates to gain leverage that enables the right institutional changes. Finally, those leaders who focus on winning strategic debates ultimately have little strategic influence and are left with less influence for negotiating institutional changes.