SCOTT SIMON, HOST:
And staying in the area of security for a moment, President Obama says that world leaders meeting in Washington, D.C., this week made what the president called significant progress in keeping terrorists from getting deadly nuclear material. The president also sharply criticized Donald Trump for suggesting that more countries should have nuclear weapons. NPR's Scott Horsley reports.
SCOTT HORSLEY, BYLINE: This week's nuclear security summit was the culmination of a six-year effort to safeguard the world's nuclear stockpiles. President Obama, who launched that effort, says it has made a difference. More than a dozen countries have gotten rid of their most dangerous uranium and plutonium stocks. Obama says all of South America is now free of such material. And by year's end central Europe and Southeast Asia will be too.
(SOUNDBITE OF ARCHIVED RECORDING)
BARACK OBAMA: As terrorists and criminal gangs and arms merchants look around for deadly ingredients for a nuclear device, vast regions of the world are now off-limits. And that is a remarkable achievement.
HORSLEY: Obama concedes the threat of nuclear terrorism is far from lifted. Some 2,000 tons of nuclear material is still scattered around the world, not all of it in secure locations.
Terrorist groups like ISIS have shown an interest in obtaining that material, if not to build an atomic weapon, then at least to magnify their killing power with a dirty bomb. Obama says countries have to do more to prevent dangerous material from falling into the wrong hands. He echoed the vision he'd spelled out during his first year in office of a world without nuclear weapons.
(SOUNDBITE OF ARCHIVED RECORDING)
OBAMA: Realizing our vision will not happen quickly. And it perhaps will not happen in my lifetime. But we've begun.
HORSLEY: Obama was asked last night about the very different vision suggested by Donald Trump. The GOP presidential candidate told The New York Times he'd be willing to let Japan and South Korea develop their own nuclear arsenals rather than relying on U.S. military protection. Such a move would reverse decades of nonproliferation policy. Obama was blunt in his rebuttal.
(SOUNDBITE OF ARCHIVED RECORDING)
OBAMA: The person who made the statements doesn't know much about foreign policy or nuclear policy or the Korean Peninsula or the world generally.
HORSLEY: The president says Trump's comments were a subject of conversation at the security summit, just as they've aroused interest and alarm at other international gatherings.
(SOUNDBITE OF ARCHIVED RECORDING)
OBAMA: What we do is really important to the rest of the world.
HORSLEY: Obama says even countries that are used to a carnival atmosphere in their own elections want sobriety and clarity from the United States. Scott Horsley, NPR News, the White House. Transcript provided by NPR, Copyright NPR.