Nuclear security

Estimates of North Korea's nuclear weapons are difficult to nail down

 The U.S. intelligence agencies' assessments of the size of North Korea's nuclear arsenal have a wide gap between high and low estimates. Size matters and not knowing makes it harder for the United States to develop a policy for deterrence and defend itself and allies in the region.

The secrecy of North Korea's nuclear program, the underground nature of its test explosions and the location of its uranium-enrichment activity has made it historically difficult to assess its capabilities.

Some U.S. assessments conclude North Korea has produced or can make around 30 to 60 nuclear weapons, said two U.S. officials who weren't authorized to discuss sensitive intelligence matters and demanded anonymity. Such a wide range affects how the U.S. considers addressing the threat. More North Korean bombs could indicate second-strike capacity and then there are questions about how much nuclear firepower the country could mobilize on a moment's notice.