Preview: How should the United States approach the Korean Peninsula and the problem of North Korean nuclear proliferation? Since its initial test in October 2006, North Korea has conducted five more, increasing the estimated yield with each one. Pyongyang’s September 2017 nuclear test—which they claimed was a thermonuclear device—had an estimated yield of between 50–280 kilotons, a significant increase from previous tests. Perhaps more alarming to U.S. policymakers, the North has surged forward with its missile program, conducting 15 missile tests in 2015, 24 in 2016, and thus far 19 missile tests in the first 10 months of 2017. The missile program rose to the height of U.S. policy concern in July 2017, when the North successfully tested the Hwasong-14, its first truly intercontinental ballistic missile, with an estimated range as great as 6,500 miles (10,400 km). Discussion has arisen as to whether, or increasingly when, North Korea will be able to marry these two technologies, and successfully mount a miniaturized nuclear warhead on a medium- or even long-range missile. The U.S. Defense Intelligence Agency (DIA) has concluded that Pyongyang has already reached this milestone, potentially putting Los Angeles, Denver, and Chicago within nuclear striking distance.Thus, time is of the essence, and more clearly on North Korea’s side as they move steadily toward a significantly more robust and threatening nuclear capability.