The Strategic Studies Institute's XXI Annual Strategy Conference, held at Carlisle Barracks from April 6-8, 2010, addressed the topic of the meaning of war. While it did not seek to produce a definitive answer to questions about the nature and definition of war, it did highlight the crucial questions and their implications, including issues such as whether the cause of war is shifting, whether all forms of organized, politically focused violence constitute war, and the distinction between passive and active war. In the report which follows, Steven Metz and Philip Cuccia of SSI have summarized the presentations and debates at the conference and placed them in their wider intellectual and strategic context,

For more than 2 decades, the Strategic Studies Institute (SSI) has hosted an annual strategy conference. Each conference was designed to convene some of the world's top experts on a major strategic issue, and to use cutting edge scholarship and analysis to help the U.S. Army and Department of Defense (DoD) leadership understand the issue. The April 2010 Strategy Conference was entitled "Defining War for the 21st Century." The conference included a keynote address by Professor Martin van Creveld, a banquet presentation by Major General (Retired) Robert Scales, and panels on the historical context; the instigation of war; the end of wars; the participants in war; the rule sets governing war; and the policy, strategy, and organizational implications of defining war. The conference speakers, which included well known scholars, former policymakers, and former senior military leaders, agreed on some points, but often had very different perspectives. Most importantly, they identified the most pressing questions that the American and international defense communities are grappling with as they refine their definition of war. In the report which follows, Steven Metz and Philip Cuccia of SSI have summarized the presentations and debates at the conference and placed them in their wider intellectual and strategic context. SSI is pleased to offer this report in fulfillment of its mission to assist U.S. Army and DoD senior leaders and strategic thinkers in understanding the key issues of the day.

The Strategic Studies Institute's XXI Annual Strategy Conference, held at Carlisle Barracks from April 6-8, 2010, addressed the topic of the meaning of war. While it did not seek to produce a definitive answer to questions about the nature and definition of war, it did highlight the crucial questions and their implications, including issues such as whether the cause of war is shifting, whether all forms of organized, politically focused violence constitute war, and the distinction between passive and active war.

The U.S. Army War College, in cooperation with the Association of the United States Army (AUSA), the U.S. Naval War College, and the Atlantic Council of the United States, cosponsored a symposium in late F%ebruary 1997 to examine the topic, ̀1National Defense into the 21st Century: Defining the Issues.'1 The purpose of this symposium was to relate the national interests of the United States to its long-term military requirements and to define those challenges which will face the Department of Defense, as well as those issues most pertinent to each of the military services. This symposium was a sincere effort by individuals from the various services, the Army1s and the Navy1s premier professional military education institutions, AUSA, and the Atlantic Council to search for a common under- standing of the difficult issues facing all the services jointly and each of them individually. Over a period of two days, through four panels and three special addresses, the presenters and more than 100 attendees engaged in an enlightening and productive exchange of ideas and points of view. What follows is a report on the four individual panels and the comments of the Honorable John D. White, the Deputy Secretary of Defense; Major General Mark K. Hamilton, U.S. Army, Vice Director for F%orce Structure, Resources, and Assessment on the Joint Staff; and retired U.S. Army General Andrew J. Goodpaster, Chairman of the Atlantic Council of the United States. General Jack N. Merritt, U.S. Army, Retired, opened the symposium by describing its goals and agenda.