In July 2017, North Korea apparently successfully tested its first intercontinental ballistic missiles (ICBMs). Combined with the long-standing use of aggressive rhetoric toward the United States by successive Kim regimes, these events appear to have fundamentally altered U.S. perceptions of the threat the Kim Jong-un regime poses, and have escalated the standoff on the Korean Peninsula to levels that have arguably not been seen since at least 1994. To a greater degree than their predecessors, however, Trump Administration officials have publicly emphasized that "all options are on the table," including the use of military force, to contend with the threat North Korea may pose to the United States and its allies. If the Trump Administration chooses to pursue military options, key questions for Congress include whether, and how, to best employ the military to accomplish denuclearization, and whether using military force on its own or in combination with other tools might result in miscalculation on either side and lead to conflict escalation. Some analysts contend, however, that the risk of allowing the Kim Jong-un regime to acquire a nuclear weapon capable of targeting the U.S. homeland is of even greater concern than the risks associated with the outbreak of war, especially given Pyongyang's long history of threats and aggressive action toward the United States and its allies and the regime's long-stated interest in unifying the Korean Peninsula on its terms. Many students of the regional military balance contend that an overall advantage over North Korea rests with the United States and its ally, the Republic of Korea (or, ROK, commonly known as South Korea), and that U.S./ROK forces would likely prevail in any conflict within a matter of weeks. Those analyses, however, also generally assume that neither China nor Russia would become engaged in the conflict. Should China or Russia do so, the conflict would likely become significantly more complicated, costly, and lengthy. As a result, Congress may consider whether to support increased U.S. military activities—possibly including combat operations—to denuclearize the Korean peninsula, or whether instead to support efforts to contain and deter North Korean aggression primarily through other means. For this reason, few analysts believe that North Korea would launch an unprovoked attack on U.S. territory or U.S. overseas bases; the consequences for doing so could include a possible overwhelming U.S. military response that could result in the end of the Kim Jong-un regime, and possibly the end of the DPRK as a sovereign state. The Republic of Korea, by contrast, has emphasized quality over quantity and maintains a highly skilled, well-trained, and capable conventional force. Pyongyang could also escalate to attacking Japan with ballistic missiles. China's Reaction

A significant factor likely affecting policymakers' deliberations regarding the use of military force on the Korean Peninsula is the question of whether a military conflict between the DPRK and the U.S./ROK runs the risk of a direct military clash with China, as occurred during the 1950-1953 Korean War. Implications for East Asia

The use of U.S. military force on the Korean Peninsula would likely have far-reaching implications for U.S. alliances and partnerships in the region, for great power politics and rivalries, and for the overall security landscape in the Asia-Pacific, and perhaps more broadly. Not all of these options are mutually exclusive, nor do they represent a complete list of possible options, implications, and risks. The following discussion is based entirely on open-source materials. CRS cannot verify whether any of these potential options are currently being considered by U.S. and ROK leaders. Opponents might also argue that maintaining the status quo may create time for sanctions to work, but also creates time for North Korea to develop a nuclear-tipped ICBM capable of reaching the U.S. homeland and for North Korea to expand the size of that capability. Deny DPRK Acquisition of Delivery Systems Capable of Threatening the United States

Pursuing this option may mean deemphasizing, at least for the immediate future, the denuclearization of the Korean Peninsula and instead focusing on mitigating, or even negating, the means of delivery of nuclear devices, in particular nuclear-tipped ICBMs. These operations are considered to be high-risk—and could incur significant military casualties—compared with attacking targets with aerial assets. If so, what actions, under what circumstances, ought to be covered by such an authorization? Applied to a postconflict situation on the Korean Peninsula, the United States military might have to respond to a number of issues in both North and South Korea. Availability of Forces for Other Contingencies

Particularly should hostilities escalate into a full-scale war between the DPRK and the U.S./ROK, the force for conducting such a military campaign and then managing its aftermath could be considerable. First, whether or not it believes the United States could or should manage and deter a nuclear-armed North Korea if it becomes capable of attacking the U.S. homeland. Second, whether taking decisive action to prevent the emergence of such a DPRK capability, including the use of military forces, might be necessary. Such determinations potentially carry considerable risks for the United States, its allies, regional stability, and global order. In Detail: The Military Balance on the Korean Peninsula
Estimating the military balance in the region, and how military forces might be employed during wartime, requires accounting for numerous variables and as such is an inherently imprecise endeavor. As an overall strategic approach, the DPRK has emphasized quantity over quality, as well as asymmetric capabilities including weapons of mass destruction and special operations forces, in building and maintaining its military. Forces Korea, U.S.
North Korea's apparently successful July 2017 tests of its intercontinental ballistic missile capabilities, along with the possibility that North Korea (DPRK) may have successfully miniaturized a nuclear warhead, have led analysts and policymakers to conclude that the window for preventing the DPRK from acquiring a nuclear missile capable of reaching the United States is closing. These events appear to have fundamentally altered U.S. perceptions of the threat the Kim Jong-un regime poses to the continental United States and the international community, and escalated the standoff on the Korean Peninsula to levels that have arguably not been seen since 1994.
A key issue is whether or not the United States could manage and deter a nuclear-armed North Korea if it were to become capable of attacking targets in the U.S. homeland, and whether taking decisive military action to prevent the emergence of such a DPRK capability might be necessary. Either choice would bring with it considerable risk for the United States, its allies, regional stability, and global order. Trump Administration officials have stated that "all options are on the table," to include the use of military force to "denuclearize"—generally interpreted to mean eliminating nuclear weapons and related capabilities from that area.
One potential question for Congress is whether, and how, to employ the U.S. military to accomplish denuclearization, and whether using the military might result in miscalculation on either side, or perhaps even conflict escalation. Questions also exist as to whether denuclearization is the right strategic goal for the United States. This is perhaps because eliminating DPRK nuclear or intercontinental ballistic missile (ICBM) capabilities outside of voluntary denuclearization, and employing military forces and assets to do so, would likely entail significant risks. In particular, any move involving military forces by either the United States/Republic of Korea (U.S./ROK) or the DPRK might provoke an escalation of conflict that could have catastrophic consequences for the Korean Peninsula, Japan, and the East Asia region.
In this report, CRS identifies seven possible options, with their implications and attendant risks, for the employment of the military to denuclearize North Korea. These options are
maintaining the military status quo, enhanced containment and deterrence, denying DPRK acquisition of delivery systems capable of threatening the United States, eliminating ICBM facilities and launch pads, eliminating DPRK nuclear facilities, DPRK regime change, and withdrawing U.S. military forces.
These options are based entirely on open-source materials, and do not represent a complete list of possibilities. CRS cannot verify whether any of these potential options are currently being considered by U.S. and ROK leaders. CRS does not advocate for or against a military response to the current situation.
Conservative estimates anticipate that in the first hours of a renewed military conflict, North Korean conventional artillery situated along the Demilitarized Zone (DMZ) could cause tens of thousands of casualties in South Korea, where at least 100,000 (and possibly as many as 500,000) U.S. soldiers and citizens reside. A protracted conflict—particularly one in which North Korea uses its nuclear, biological, or chemical weapons—could cause enormous casualties on a greater scale, and might expand to include Japan and U.S. territories in the region. Such a conflict could also involve a massive mobilization of U.S. forces onto the Korean Peninsula, and high military casualty rates. Complicating matters, should China choose to join the conflict, those casualty rates could grow further, and could potentially lead to military conflict beyond the peninsula. Some analysts contend, however, that the risk of allowing the Kim Jong-un regime to acquire a nuclear weapon capable of targeting the U.S. homeland is of even greater concern than the risks associated with the outbreak of regional war, especially given Pyongyang's long history of bombastic threats and aggressive action toward the United States and its allies and the regime's long-stated interest in unifying the Korean Peninsula on its terms.
Estimating the military balance on the peninsula, and how military forces might be employed during wartime, requires accounting for a variety of variables and, as such, is an inherently imprecise endeavor. As an overall approach to building and maintaining its forces, the DPRK has emphasized quantity over quality, and asymmetric capabilities including weapons of mass destruction and its special operations forces. The Republic of Korea, by contrast, has emphasized quality over quantity, and maintains a highly skilled, well-trained, and capable conventional force. Most students of the regional military balance contend that overall advantage is with the U.S./ROK, assuming that neither China nor Russia become involved militarily. Should they do so, the conflict would likely become exponentially more complicated.
As the situation on the Korean Peninsula continues to evolve, Congress may consider whether, and if so under what circumstances, it might support U.S. military action. Congress could also consider
the risks associated with the possible employment of military force on the Korean Peninsula against North Korea; the efficacy of the use of force to accomplish the Trump Administration's strategic goals; whether and when a statutory authorization for the use of U.S. forces might be necessary, and whether to support such an authorization; what the costs might be of conducting military operations and postconflict reconstruction operations, particularly should a conflict on the Korean Peninsula escalate significantly; the consequences for regional security, regional alliances, and U.S. security presence in the region more broadly; and the impact that renewed hostilities on the Korean Peninsula might have for the availability of forces for other theaters and contingencies.