The limitations of America's land forces remain a fundamental constraint on U.S. military strategy. The cutbacks of the Clinton years and the Bush administration's failure to foresee the need for larger ground forces in the wake of 9/11 have undercut America's ability to fight the Long War. Resolving the stark divergence between America's military ends and means--in terms of force size, training, and modernization--will be a crucial challenge for the next administration.

In Ground Truth: The Future of U.S. Land Power, Thomas Donnelly and Frederick W. Kagan pose five urgent questions for policymakers: What is the strategic role of American ground forces? What missions will these forces undertake in the future? What is the nature of land warfare in the twenty-first century? What qualities are necessary to succeed on the battlefields of the Long War? What is the ideal size and configuration of the force--and how much will it cost?

Answers to such questions are long overdue. The stresses of prolonged operations in the Middle East have strained the U.S. Army and Marine Corps; if the United States is to maintain its status as the sole superpower, American land power must be restructured to confront unprecedented challenges.

Only a dedicated, bipartisan effort can create a ground force that is not only larger and more flexible, but retrained and reequipped. Donnelly and Kagan provide a plan of action for policymakers to begin that vital rebuilding.

Thomas Donnelly is a resident fellow in defense and security policy studies at the American Enterprise Institute. Previously, he served as policy group director and professional staff member for the House Armed Services Committee.

Frederick W. Kagan is a resident scholar in defense and security policy studies at the American Enterprise Institute. He was formerly an associate professor of military history at the U.S. Military Academy at West Point.