Research Questions

  1. Are the current U.S. ground forces sufficient to address national security commitments?
  2. How can the U.S. Army — as part of a joint, interagency, intergovernmental, and multinational force — help the nation achieve its highest-level national security interests and mitigate the most important risks?
  3. What proportion of active and reserve component ground forces would need to mitigate prospective security risks?

This report makes three essential points: The world has changed following the foundational defense planning in the 2014 Quadrennial Defense Review; emerging and growing threats increase the likelihood that U.S. commitments in key regions will be challenged; and planned cuts to the U.S. Army will result in too few ground forces to satisfy declared commitments. In light of these concerns, this report addresses the U.S. Army capacity needed — as part of a joint, interagency, intergovernmental, and multinational force — to help the nation achieve its highest-level national security interests and mitigate the most important risks. The authors consider the terror threat in North Africa, the Middle East, and Afghanistan; potential Russian aggression against NATO Baltic states; and the threats posed by North Korea, including "loose nukes." In these three contexts, the authors assess the capability of the nation to satisfy existing commitments, given planned force reductions to the U.S. Army. The authors outline shortcomings and propose actions necessary to maintain an Army of sufficient force to satisfy U.S. commitments, meet threats with force, and avoid strategic failure and regret.

Key Findings

The United States Has Insufficient Ground Forces to Meet the Demands of Three Key Missions

  • The analysis assessed whether current U.S. ground forces were sufficient to respond to three of the largest U.S. national security commitments — combatting the persistent threat of terrorism, assuring allies and deterring aggression in multiple theaters, and preventing the spread and use of WMD.
  • Force planning did not anticipate the scope and scale of ISIL threats or the Russian invasion of the Ukraine and does not account for Russia's potential threat to NATO Baltic states. Likewise, the scope and scale of defeating North Korean artillery attacks or eliminating the North Korean WMD program requires more than the current and planned forces.
  • The United States has insufficient ground forces — including Army and Marine Corps forces — to meet the demands of these missions.
  • Responding to multiple threats would require the Army and Marine Corps to deploy a proportion of active and reserve forces significantly higher than historical levels.
  • The planned decreases in Army end strength will exacerbate the national security risk and decrease the likelihood that our nation can satisfy international commitments.
  • Even less margin is available for meeting unforeseeable challenges, which may be more demanding in the aggregate than those the nation and its leaders can envisage.


  • DoD should pause the current drawdown of Army active and reserve component soldiers until the threat of Russian aggression against NATO states in the Baltics has receded. These additional troops could be funded with overseas contingency operations funds.
  • DoD should resource the highest possible readiness levels in both the active and reserve components.
  • DoD should establish plans for total mobilization of the National Guard and Reserve components — something the nation has not done since World War II.
  • The Army should regularly test the readiness of complete active and reserve units.
  • DoD should increase the Army's ground force posture in the Baltics and South Korea to speed deployment times. This would entail building the war-supporting infrastructure required, maintaining armored brigades and supporting forces in the Baltics, and assessing a variety of options to rotate or permanently station them there. The United States should also consider options to preposition equipment in both the Baltics and Korea as a deterrent and to speed deployment.

This research in the public interest was supported by RAND, using discretionary funds made possible by the generosity of RAND's donors and the fees earned on client-funded research.

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