On September 23, President Trump tweeted that North Korean leaders “will not be around much longer” if they continue to threaten the United States and characterized Kim Jong-Un as “Little Rocket Man.” On September 25, Foreign Minister Ri Yong-ho called President Trump’s comments a “declaration of war” and threatened to shoot down U.S. warplanes, even if they are outside the country’s airspace. The escalating tension between North Korea and the United States raises the possibility of U.S. involvement in a regional conflict with a nuclear adversary. Based on its recent nuclear and missile tests, North Korea may not be able to reach the continental United States with a missile carrying a nuclear weapon. However, the country already has the capability to deliver nuclear weapons by aircraft, ship, and perhaps by theater ballistic missiles, which could credibly target U.S. military forces in South Korea, Japan, or Guam. According to DOD data, the United States has about 39,000 military forces in Japan; 23,000 in South Korea; and 4,000 in Guam. If a conflict were to arise and nuclear weapons were introduced, U.S. forces may need to maneuver and operate in a nuclear environment. Given the volatility between North Korea and the United States, it behooves U.S. leaders to deliberate on whether the preparedness of U.S. forces to operate in such conditions needs renewed attention. The Defense Science Board issued a series of reports, including in 2010, 2011, and 2016, that discussed the survivability of U.S. conventional forces—general-purpose forces—in a nuclear environment. The reports offer a sobering and unnerving account of the theater nuclear survivability of U.S. general-purpose forces. As bluntly put in the 2011 report: “The survivability, effectiveness, and adaptation of general-purpose forces is at best unknown. If they were subjected to a nuclear event in the foreseeable future, mission execution would depend upon combinations of luck and ingenuity in workarounds for failed equipment. There would almost certainly be an unnecessarily high human cost.” The reports’ grim outlook for the survivability of U.S. forces is rooted in part in the loss of awareness within general-purpose forces of how to deal with nuclear weapons effects and plan for military operations in nuclear environments. As noted in the 2016 report, general knowledge in the military does not exist on nuclear weapons and the environments they generate, outside of some in the Air Force and Navy strategic force cadres and a small group of specialists in the Army. The 2011 report characterizes this gap in knowledge as a “serious and potentially show-stopping issue.” The reports also express concern over the survivability of military capabilities in a theater nuclear environment. Referencing the ubiquitous dependence in military and commercial systems on commercial off-the-shelf components, the reports note that the response for virtually all of these devices to nuclear weapons effects is unknown. The 2010 report elaborates on this point, indicating that command, control, and communications systems; conventional fighting platforms and vehicles; intelligence, surveillance, and reconnaissance systems; and logistics, repair, and maintenance systems are reliant on commercial components that may be highly susceptible to a nuclear attack. This concern—coupled with the decline in requirements, testing, and evaluation for the nuclear survivability of conventional systems—creates uncertainty for how well, if at all, these systems would work in a nuclear contingency. The 2011 Defense Science Board report indicates that progress had been made from 2009 to 2011 on some of these issues and more progress has likely been made since then. However, it is unclear whether these issues routinely receive high-level visibility and priority. The 2010 Nuclear Posture Review Report completed by the Office of the Secretary of Defense for Policy did not address nuclear survivability for conventional operations, consistent with prior nuclear posture review reports, and the 2011 Defense Science Board notes that policy representatives indicated this area was not on the “radar screen” during the 2010 review. U.S. nuclear policy has focused on the deterrence of a nuclear conflict, not on the management of a nuclear conflict. That focus is entirely appropriate. Even a one-kiloton nuclear weapon—a much smaller-yield weapon than was recently tested by North Korea—detonated in Seoul could kill up to 92,000 people. The use of these weapons is unconscionable and thus our primary goal should be to ensure they aren’t used. But not all potential nuclear conflicts are the same. A conflict that crosses the nuclear threshold could turn into a Strangelovian disaster or it could be managed so that the escalation could be limited. Despite our best efforts, deterrence could fail, and we should be prepared for that possibility. The Pentagon is currently in the midst of a subsequent nuclear posture review. Whether nuclear survivability of U.S. forces receives attention will be key in understanding the importance that DOD and the administration place on this issue. Given the potential for a conflict with a nuclear adversary, our ability to ensure that our general-purpose forces have the appropriate expertise and equipment to plan and operate in nuclear conditions would seem to be a critical requirement.