WASHINGTON (March 10, 2010) -- The model used to determine the appropriate size of the United States military is being replaced following the Quadrennial Defense Review process, a senior defense official said here today.

Speaking on background at a two-day seminar on the 2010 Quadrennial Defense Review hosted by the National Defense University, the official said the theory that U.S. forces should be sized based on the need to fight two major wars simultaneously no longer is appropriate.

"We're looking for the broadest range of capabilities to deal with the broadest range of scenarios," he stated. "It's not as easy to talk about ... as the two major theater war paradigm, but it's important, and it's essential to our preparation for future conflict."

The 2010 QDR, released Feb. 1, is a comprehensive review of Defense Department strategy and priorities, closely tied to the defense budget. The report identified several key goals for the department in the next decade.

The QDR's overarching themes are two-fold: rebalancing U.S. military capabilities and reforming defense processes and institutions. This, the report states, will enable the military to prevail in today's wars, prevent and deter future conflict, prepare to defeat potential adversaries, and preserve and enhance the all-volunteer force.

Rather than focusing on preparing to fight two major wars at the same time to achieve these goals, the military instead must prepare to "succeed in a wide range of contingencies," the official said.

While this decision signals a major change in a policy that has been the staple of U.S. force planning since the 1990s, the official emphasized that this new direction was, in fact, a continuation of the previous administration's work in the 2006 QDR.

"I want to give credit to the previous QDR and its alternative force planning construct," the official said. "We were able to build off of that [for this review]."

The new force-sizing paradigm for the short term accounts for ongoing operations in Iraq and Afghanistan as well as "foundational activities" to prevent and deter conflict from both transnational terrorist threats and potential state adversaries. In addition, the military will be outfitted with sufficient forces to support civilian authorities for emergency relief missions.

"The forces required to do operations in Haiti obviously present a challenge given the strains on the force, but we've already demonstrated since the QDR's [release] that despite the ongoing operations, the Department of Defense is capable of bringing additional capabilities to bear to deal with emerging challenges," he said.

In trying to determine an appropriate force-sizing model for the mid-to-long term, the review team considered various combinations of operations that the military could face at any one time, the official said. These included stabilization operations, defeating a state with anti-access capabilities, supporting civil authorities, and combinations of those possibilities, along with other possible contingencies.

The QDR group then looked to "mix and match" from those categories to determine likely scenarios with which the military might be confronted, and determined force structure based on requirements needed to meet those challenges.

One of the scenarios, defeating two regional aggressors along with heightened alert posture in or around the United States, probably is the "closest to our old planning program," the official noted. However, "it's only one of a number of options that were considered."

Recognizing that this new construct didn't convert simply into a numerical equation, the official nonetheless remained confident in its efficacy.

"It's intended to be a realistic assessment of the type of demands our forces may face in the future," he said.