If unchecked, North Korea is increasingly likely to resume strategic weapons testing in the months ahead—including tests of the technologies necessary for its missiles to carry multiple nuclear-capable reentry vehicles (RVs). Such missiles would, at a minimum, increase Pyongyang’s ability to challenge U.S. missile defenses, to make the most of its limited resources for strategic weapons production, and to threaten U.S. targets more credibly despite its limited flight testing of RVs.