No matter how bad the problem, a former colleague of mine used to always preface discussions by saying that it represented an "opportunity." The Sequester's cuts will hit the Department of Defense (DOD) especially hard. But rather than focus on the cuts, I suggest we see this as an opportunity to assess and better align America's national security interests and capabilities.Half of the anticipated $85 billion in sequestration cuts will come from the DOD. That figure, $42.5 billion, represents about seven percent of the DODs budget (including funding for ongoing conflicts in addition, a small percentage of the cuts could also come from the Departments of Energy and Homeland Security). Over the next decade, the Sequester would reduce DOD funding by almost $500 billion.What would these cuts mean? On one hand, seven percent doesn't seem that much. In fact, cutting just one weapons program, the problematic F-35 fighter jet, would cover almost all of the DODs fiscal reductions for the entire decade. On the other hand, experts in and outside of the DOD claim these cuts will devastate the military and fundamentally degrade American security. To understand how to assess competing claims regarding the impact of these cuts, we have to look at the factors that drive the U.S. defense budget. It is widely reported that the U.S. spends more on defense than the states with the ten next largest militaries combined. Four factors contribute to America's high defense spending. First, the U.S. has a volunteer force. Even in the face of recession, the military has to compete with the private sector (and other government agencies) to attract and retain qualified personnel. Keep in mind that there are almost 1.5 million active duty and many more Reserve and Guard troops in uniform.Other large militaries, such as China, face dramatically lower military labor costs. While military pay is excluded from Sequester cuts, other major expenses, such as housing that affects the quality of life stateside as well as minor expenses, like access to the internet in Afghanistan, all contribute to retention. Second, the DOD spends a lot to minimize the risk faced by American military personnel. These efforts include direct effects, such as body armor and tactical drones that can see around a bend in the road, or indirect effects, such as improved search and rescue operations and innovative computerized visualization technologies that working together has reduced to amazingly small figures the number of American missing in action and prisoner of war casualties. These technologies are all very, very costly. In a basic sense, there is a tradeoff between dollars spent and U.S. military lives lost. Third, the U.S. has been in a state of war and its resulting up-tempo level of operations for more than a decade. Combat has direct and indirect costs. The White House requested $88.5 billion in funds to cover overseas operations (in addition to the $525.4 billion requested for the DOD). This $88.5 billion however doesn't come close to covering the indirect costs of up-tempo operations, such as the accelerated maintenance necessary to keep complex weapons systems operational or the higher trainings costs resulting from the loss of personnel, either as casualties or through decreased retention rates. The U.S. has been drawing military resources from across the globe to fund the wars in Iraq and Afghanistan an act that can be thought of as dipping into the savings account to cover bounced checks. The result is that the wars in Iraq and Afghanistan have resulted in lower levels of readiness and reduced global capabilities. But the fourth and arguably most important reason that the U.S. spends more than any other country on defense is that the U.S. has the most ambitious foreign policy in the world. No other country comes close to pursuing vast number of global (every continent, every regional of the world), multi-dimensional (WMD, terrorists, cyber-security, space-based systems) national security objectives of the US. The result: U.S. forces are over extended. They are over-extended in terms of time fighting two wars and many other skirmishes around the globe over the last decade has taken a tremendous toll on men and machines. They are over extended in terms of space the U.S. has troops in dozens of countries around the globe, interests in almost every region of the world, and in the face of falling resources has begun to energize its new Africa command (AFRICOM). But most importantly, U.S. military forces are over extended in terms of missions. The U.S. military is just trying to do too much. Every mission, whether it is central to American national security, such as the defense of the American homeland, or more peripheral, such as the use of more than a thousand American troops to search for insurgents in the Philippines, or not even directly national security, such as the provision of humanitarian aid after disasters like earthquakes, requires people, resources and perhaps most limiting - thought. Leaders have to prepare for, plan, execute and assess every mission, creating a major mental drain on the U.S. national security establishment. Thus, while the U.S. may spend more than the next ten largest militaries combined, it also tries to do more than they do. The Sequester represents an opportunity to balance better the vast and varied list of missions it pursues and its enormous, but not infinite, resources The Sequester embodies an opportunity for U.S. national security leadership to make difficult decisions, eliminating some traditional missions and seeking to pursue others in fundamentally different ways, in order to maintain the resources and focus necessary to meet American national security needs today and in the future.The Sequester should engage American leadership in conversation about critical national security topics, such as the future of NATO, the need for all legs of the nuclear triad, and the necessity of maintaining U.S. troops in rich and powerful countries like Korea and Japan. The worst outcome, however, would be for the DOD to absorb the mandated cuts without a resulting reduction in missions. Funding cuts without mission reductions might push an already overstretched U.S. military past the breaking point, potentially damaging U.S. national security interests and overtaxing already strained troops.ABOUT THE WRITERScott Sigmund Gartner is a Professor at Penn States School of International Affairs and Dickinson School of Law. Author of Strategic Assessment in War (Yale University Press), he is currently studying the political and strategic factors that contribute to suicide in the military.McClatchy Newspapers did not subsidize the writing of this column; the opinions are those of the writer and do not necessarily represent the views of McClatchy Newspapers or its editors.