The following editorial first appeared in the Philadelphia Inquirer:
President Obama's leadership of a 47-nation summit on nuclear weapons was focused on the right goal-preventing terrorists from getting their hands on nukes.
World leaders need to work together with a sense of urgency to secure nuclear arsenals and to share information on extremists trying to obtain weapons of mass destruction. Obama's emphasis on diplomacy makes such cooperation more likely.
Obama also won a pledge from foreign leaders to meet his goal of securing all nuclear materials within four years. This commitment is nonbinding, but the issue is worth the high-level attention the president is bringing to it.
Just two months after the terrorist attacks of Sept. 11, 2001, Osama bin Laden met with the former operator of a plutonium reactor in Pakistan. They discussed how to build a nuclear weapon, but the Pakistani man told bin Laden that it would be too difficult to develop materials that could be used in a weapon. Bin Laden reportedly replied, "What if I already have them?"
If he didn't have them yet, the world has plenty of locations where he could try to get them. Russia alone stores uranium and plutonium at more than 200 sites. At least eight nations have nuclear weapons, and dozens of countries possess more than 2,000 tons of plutonium and uranium.
Russia and the United States announced that they will move ahead with a long-delayed agreement to dispose of 34 tons of plutonium each - enough to build 17,000 nuclear weapons. When this process begins in 2018, both countries still would have 1,550 nuclear warheads.
The most glaring loose ends from this summit in Washington involve Pakistan, Iran, and North Korea.
These voluntary agreements won't affect Iran's push to develop nuclear weapons, the prospect that keeps Gen. David Petraeus of U.S. Central Command awake at night. Obama is pursuing sanctions against Iran at the United Nations but is encountering reluctance from China, which is the third-largest importer of Iranian crude oil.
Pakistan, a base for al-Qaeda, said it will resist international efforts to ban production of more bomb materials. Pakistanis harbor a deep mistrust of India, their nuclear neighbor. Securing Pakistani weapons programs will remain one of the United States' most serious challenges.
North Korea, a wild card as usual, did not participate in the nuclear summit. The global community conveyed its seriousness about containing nuclear arsenals by scheduling its next summit in South Korea.
Obama is showing needed leadership by focusing the world's attention on nuclear security. But he will need to put more pressure on foreign leaders to produce further tangible results on this critical issue.