I do not bring with me today a definitive solution to the problems of war. What I do know is that meeting these challenges will require the same vision, hard work, and persistence of those men and women who acted so boldly decades ago. And it will require us to think in new ways about the notions of just war and the imperatives of a just peace.
We must begin by acknowledging the hard truth: We will not eradicate violent conflict in our lifetimes. There will be times when nations -- acting individually or in concert -- will find the use of force not only necessary but morally justified.
-- remarks by President Obama as he accepted the Nobel Peace Prize