MARY LOUISE KELLY, HOST:
Here in Washington, it has been a week of canine bomb-sniffing teams and traffic snarls and motorcades as world leaders gathered for the fourth and final Nuclear Security Summit. President Obama started hosting these summits to achieve one of his signature goals - preventing nuclear stockpiles from falling into the hands of terrorists. NPR's Scott Horsley reports.
SCOTT HORSLEY, BYLINE: This week, President Obama called nuclear terrorism a perfect example of a 21st-century security challenge, the kind no one nation can solve on its own.
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BARACK OBAMA: I convened our first summit six years ago in this same room because the danger of a terrorist group obtaining and using a nuclear weapon is one of the greatest threats to global security.
HORSLEY: Six years later, Harvard's Matthew Bunn says leaders have made substantial progress. They've tried to beef up security around nuclear installations, and more than a dozen countries, including Ukraine, got rid of their highly-enriched uranium and plutonium.
MATTHEW BUNN: Aren't we all glad that the potential bomb material wasn't in Ukraine anymore when the fighting started?
HORSLEY: At the same time, Bunn says, there are still a lot of vulnerable stockpiles left. Obama says terrorist groups, like the self-proclaimed Islamic State, are always on the lookout for new tools to wreak havoc.
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OBAMA: There is no doubt that if these madmen ever got their hands on a nuclear bomb or nuclear material, they most certainly would use it to kill as many innocent people as possible.
HORSLEY: In the run-up to this week's summit, a number of countries signed onto a treaty requiring them to handle nuclear material in a secure way. But Kelsey Davenport of the Arms Control Association says because that treaty focuses on civilian material, it doesn't go far enough.
KELSEY DAVENPORT: That's an area where the summit process could have done more. There are huge stockpiles, particularly in the United States and Russia, of weapons usable nuclear material that are dedicated for military purposes.
HORSLEY: Obama says the U.S. Navy is exploring new ways to power its nuclear fleet that wouldn't require as much highly-enriched uranium. But Tom Collina of the antinuclear Ploughshares Fund complains the Pentagon is still too invested in building nuclear weapons.
TOM COLLINA: As we're controlling and securing nuclear material around the world, the world is still producing nuclear material. And in fact, it's producing it faster than we can control it.
HORSLEY: Collina and others say Obama deserves credit for curtailing Iran's nuclear program and for sounding the alarm about nuclear terrorism. Now that the president has wrapped up his last security summit, Harvard's Bunn says there's a big question mark about what happens next.
BUNN: I think a lot will depend on who the next president is and whether they are as committed to getting this material locked down.
HORSLEY: The security summit is part of Obama's larger ambition of a world free of nuclear weapons. He repeated that goal may not be achieved in his lifetime, but, he added, we've begun. Scott Horsley, NPR News, the White House. Transcript provided by NPR, Copyright NPR.
