Standing at Berlin’s historic Brandenburg Gate, President Obama reaffirmed his commitment to end the threat of nuclear weapons. “So long as nuclear weapons exist, we are not truly safe,” he declared to waves of applause. Obama promised bold cuts in strategic and tactical nuclear weapons and pledged again to prevent more nations from acquiring nuclear weapons, ban nuclear testing, and end production of bomb materials. But the president delayed implementing any of these steps pending further reviews and discussions. It is thus unclear if the much-anticipated speech will generate the active cooperation from members of the United Nations that is needed to reduce nuclear dangers.