There is much discussion in the halls of the Pentagon these days about the role of the Army, and I'd like to share with you my thoughts on the issue.Without question, 10 years of war and today's austere economic environment will have a profound impact on our Army.But to put it simply: in these uncertain times – perhaps especially in these uncertain times – the Army is central to our nation's defense.Specifically, the Army has three roles to play.First, our Army must prevent conflict.Prevention requires a credible force with sufficient capacity, readiness and modernization.Our ability and will to win any fight cannot be open to challenge.As part of a joint force, we must be clear that we can fight and win across the full spectrum of conflict. That means realistic training, expert leaders, modern equipment, and quality soldiers.Prevention is achieved by convincing your potential opponents that armed conflict with your force would be extremely unwise.Our land forces must continue to be a credible force around the globe.Second, our Army must help shape the international environment so our friends are enabled and our enemies contained.We do that by engaging with our partners, fostering mutual understanding through military-to-military contacts, and helping partners build the capacity to defend themselves.This is an investment in the future, and an investment we cannot afford to forego. It is cultivating friends before you need them, being a reliable, consistent, and respectful partner.Finally, we must be ready to win decisively and dominantly.If we do not, we pay the price in American lives.When MacArthur said, "In war there is no substitute for victory," he was making a plain statement of fact.Nothing else can approach what is achieved by winning, and the consequences of losing at war are usually catastrophic.With so much at stake, the American people will expect what they have always expected of us: to never lightly enter into such a terrible endeavor, but once there to win and win decisively.This "prevent, shape, win" construct captures the Army's unique role as part of the joint force, and rests upon the capabilities, depth, and vast experience resident within our Army.When combined with the capabilities of the Navy, the Air Force, and the Marines, the United States remains – and will remain – a force to be reckoned with.As we, the Army, continue to adapt to future strategic challenges, including resource constraints, we must ensure sufficient attention to each role.