Scott Snyder for the Council on Foreign Relations: Since Kim Jong-un came to power in 2012, he has used nuclear weapons development — a legacy of his father’s rule — as a pillar of the regime’s national strategy.

In addition to expanding its nuclear strike capabilities by conducting nuclear and missile tests, North Korea also has built a light-water nuclear reactor and uranium enrichment facility and restarted its five-megawatt nuclear reactor at Yongbyon, enabling the country to slowly build its nuclear fuel stockpile. Recent estimates suggest that North Korea’s nuclear weapons stockpile comprises 10 to 16 nuclear weapons, and could grow rapidly by 2020 to a low-end estimate of 20 weapons and a high-end estimate of 125 weapons …