In late September, leaders at the United Nations and the G-20 summit in Pittsburgh committed themselves to all these goals. Yet in the midst of those meetings, President Obama, British Prime Minister Gordon Brown and French President Nicolas Sarkozy revealed that Iran had been secretly building a second enrichment facility with the potential to produce weapons-grade uranium. That ominous development dramatized the urgent need for renewed political will in support of arms control, nonproliferation and disarmament.

The U.S. and Russia must lead the world in reducing the risks associated with nuclear weapons. Since they possess 96 percent of the world's nuclear weapons, they can, together, significantly lower the global stockpile while at the same time setting an example for other...