One urgent example is the effort to prevent the spread of nuclear weapons, and to seek a world without them. In the middle of the last century, nations agreed to be bound by a treaty whose bargain is clear: all will have access to peaceful nuclear power; those without nuclear weapons will forsake them; and those with nuclear weapons will work toward disarmament. I am committed to upholding this treaty. It is a centerpiece of my foreign policy. And I am  working with President Medvedev to reduce America and Russia's nuclear stockpiles.