North Korea

Assessing Threats to U.S. Vital Interests

North Korea

Nov 17, 2020 10 min read

North Korea
The Heritage Foundation

Bruce Klingner

With its active and growing ballistic missile capability, North Korea poses definite threats to the U.S. homeland in addition to contributing to the general threat of regional war in Asia and threatening U.S. bases in South Korea, Japan, and Guam. North Korean belligerence toward the United States has included military and diplomatic threats. Pyongyang’s provocative behavior also includes nuclear and missile tests and tactical-level attacks on South Korea, a critical American ally that remains under active threat of attack and invasion from the North. Japan faces both intimidation attacks intended to deny the U.S. its base access to Japan and nuclear attacks on U.S. bases in the case of conflict on the Korean Peninsula.

Threats to the Homeland

North Korea has developed a spectrum of missile systems that threaten the continental United States as well as U.S. forces and allies in Asia with nuclear weapons. In March 2020, General Terrence O’Shaughnessy, Commander, U.S. Northern Command and North American Aerospace Defense Command (NORAD), testified that “[i]n 2017, North Korea successfully tested an apparent thermonuclear weapon as well as two ICBM designs capable of ranging most or all of North America—feats only the five permanent members of the UN Security Council had previously achieved.”1

In July 2019, U.S. Forces Korea assessed that North Korea’s Hwasong-15 ICBM has a range of 8,000 miles and is capable of reaching anywhere in the U.S. mainland.2 Although North Korea has not yet conducted an ICBM flight test that successfully demonstrated a reentry vehicle capability, the CIA has assessed that Pyongyang’s ICBM reentry vehicles would likely perform adequately if flown on a normal trajectory to continental U.S. targets.3

North Korea has conducted six nuclear tests, including a 2017 test of a much more powerful hydrogen bomb with an explosive yield approximately 10 times the yields of the Hiroshima and Nagasaki atomic bombs of World War II. Pyongyang also has done nothing to indicate that it intends to abide by U.N. resolutions that require the abandonment of its nuclear and missile programs. North Korea has declared that it already has a full nuclear strike capability, even altering its constitution to enshrine itself as a nuclear-armed state.4 In April 2018, Kim Jong-un announced that North Korea had successfully completed its program to mount nuclear weapons on ballistic missiles and that it was no longer necessary to conduct nuclear or ICBM tests.5

In 2016 and 2017, North Korea had breakthrough successes with many missiles in development. It successfully test-launched the Hwasong 12 intermediate-range ballistic missile, which can target critical U.S. bases in Guam, and both the Pukguksong-2 road-mobile medium-range ballistic missile and the Pukguksong-1 submarine-launched ballistic missile (SLBM).6 In 2019, North Korea conducted 26 missile launches and unveiled five new short-range missile systems that threaten South Korea. That was the highest-ever annual number of North Korea’s violations of U.N. resolutions. In March 2020, Pyongyang conducted another nine short-range missile launches, all violations of U.N. resolutions.

In June 2018, President Donald Trump met with Kim Jong-un in Singapore and subsequently declared that “there is no longer a nuclear threat from North Korea” and that “total denuclearization…has already started taking place.”7 Secretary of State Michael Pompeo repeatedly claimed that North Korean leader Kim Jong-un had accepted U.N.-mandated complete, verifiable, and irreversible dismantling of his nuclear, missile, and biological and chemical weapons (BCW) programs. However, during the February 2019 Trump–Kim summit, it became clear that Kim has not agreed to do so and that the two sides still do not even have a common definition of “denuclearization” or what constitutes the Korean Peninsula.

Despite three U.S.–North Korea summit meetings, there has been no decrease in North Korea’s weapons of mass destruction (WMD) arsenal or production capabilities. The U.S. Intelligence Community subsequently assessed that Pyongyang had increased its production of fissile material for nuclear weapons, and satellite imagery showed upgrades to missile, reentry vehicle, missile launcher, and nuclear weapon production facilities.8 The Intelligence Community continues to assess that North Korea “is unlikely to give up all of its WMD stockpiles, delivery systems, and production capabilities.”9

Threat of Regional War

North Korea’s conventional and nuclear missile forces threaten U.S. bases in South Korea, Japan, and Guam. North Korea has an extensive ballistic missile force and has deployed approximately 800 Scud short-range tactical ballistic missiles, 300 No-dong medium-range missiles, and 50 Musudan intermediate-range ballistic missiles. The Scud missiles threaten South Korea, the No-dong can target all of Japan and South Korea, and the Musudan and Hwasong-12 intermediate-range ballistic missiles can hit U.S. bases on Okinawa and Guam.10

North Korea has “more than 1 million soldiers, making it the world’s fourth-largest military,” with reserves numbering several million more. In addition, “[a]bout 70 percent of [its] ground forces and 50 percent of its air and naval forces are deployed within approximately 60 miles of the Demilitarized Zone (DMZ),” making it possible to attack “with little to no warning,” which is of particular concern because South Korea’s capital, Seoul, is only 30 miles south of the DMZ.11 In addition to three conventional corps along the DMZ, Pyongyang has deployed two mechanized corps, an armor corps, and an artillery corps.

The April 2018 inter-Korean summit led to bilateral pledges of nonaggression and mutual force reduction. Similar pledges were also contained in the 1972, 1992, 2000, and 2007 joint statements, all of which Pyongyang subsequently violated or abrogated. None of those pledges prevented North Korea from conducting provocations, attempted assassinations of South Korea’s president, terrorist acts, military and cyberattacks, and acts of war.

In September 2018, the two Koreas signed a Comprehensive Military Agreement to ease military tension and build confidence. The agreement seeks to reduce the danger that inadvertent tactical military clashes along the DMZ might escalate to larger strategic conflicts. However, static defensive positions like fixed concrete bunkers and minefields are not threatening and have never been the source of military clashes on the peninsula. Rather, the greatest danger arises from the forward, offensively oriented disposition of North Korea’s forces and the regime’s history of making threats and initiating hostilities. The confidence-building measures implemented to date have not reduced North Korea’s tactical or strategic conventional military threat to South Korea, nor do they represent progress in denuclearization.

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Due to a predicted shortfall of 18-year-old conscripts by 2025, South Korea has initiated a comprehensive defense reform strategy to transform its military into a smaller but more capable force to deal with the North Korean threat. Overall, South Korean military manpower will be reduced by approximately 25 percent, from 681,000 to 500,000. The army would face the largest cuts, disbanding four corps and 23 divisions and cutting troops from 560,000 in 2004 to 370,000 in 2020. Seoul planned to compensate for decreased troop levels by procuring advanced fighter and surveillance aircraft, naval platforms, and ground combat vehicles.12

That North Korea’s conventional forces are a very real threat to South Korea was vividly demonstrated by two deadly attacks on South Korea in 2010. In March, a North Korean submarine sank the South Korean naval corvette Cheonan in South Korean waters, killing 46 sailors. In November, North Korean artillery shelled Yeonpyeong Island, killing four South Koreans.

Because the North Korean military is equipped predominantly with older ground force equipment, Pyongyang has prioritized deployment of strong asymmetric capabilities that include special operations forces, long-range artillery, and missiles. As noted, North Korea has deployed hundreds of Scud short-range ballistic missiles that can target all of South Korea with explosive, chemical, and biological warheads. The land and sea borders between North and South Korea remain unsettled, heavily armed, and subject to occasional, limited armed conflict.

North Korean forces arrayed against American allies in South Korea and Japan are substantial, and North Korea’s history of provocation is a consistent indicator of its intent to achieve its political objectives by at least the threat of force. After assuming power, Kim Jong-un directed the North Korean military to develop a new war plan to invade and occupy South Korea within a week using asymmetric capabilities that include nuclear weapons.13 Since then, North Korea has conducted several missile exercises and subsequently announced that they were practice drills for preemptive nuclear attacks on South Korea and Japan.14


The North Korean military poses a security challenge for American allies South Korea and Japan, as well as for U.S. bases in those countries and Guam. North Korean officials are belligerent toward the United States, often issuing military and diplomatic threats. Pyongyang also has engaged in a range of provocative behavior, including nuclear and missile tests and tactical-level attacks on South Korea.

North Korea has used its missile and nuclear tests to enhance its prestige and importance domestically, regionally, and globally and to extract various concessions from the United States in negotiations over its nuclear program and various aid packages. Such developments also improve North Korea’s military posture. U.S. and allied intelligence agencies assess that Pyongyang has already achieved warhead miniaturization, the ability to place nuclear weapons on its medium-range missiles, and an ability to reach the continental United States with a missile.

This Index therefore assesses the overall threat from North Korea, considering the range of contingencies, as “testing” for level of provocation of behavior and “gathering” for level of capability.

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  1. General Terrence J. O’Shaughnessy, U.S. Air Force, Commander, United States Northern Command and North American Aerospace Defense Command, statement before the Subcommittee on Strategic Forces, Committee on Armed Services, U.S. House of Representatives, March 12, 2020, p. 7, (accessed June 12, 2020).
  2. Yonhap News Agency, “Most of America in Reach of North’s Missile,” Korea JoongAng Daily, July 12, 2019, (accessed June 12, 2020).
  3. Ankit Panda, “US Intelligence: North Korea’s ICBM Reentry Vehicles Are Likely Good Enough to Hit the Continental US,” The Diplomat, August 12, 2017, (accessed June 12, 2020).
  4. Yonhap News Agency, “N.K. Calls Itself ‘Nuclear-Armed State’ in Revised Constitution,” The Korea Herald, May 30, 2012, (accessed June 12, 2020).
  5. Korean Central News Agency, “Third Plenary Meeting of Seventh C.C., WPK Held in Presence of Kim Jong Un,” April 21, 2018, (accessed June 12, 2020).
  6. Joshua Berlinger, “North Korea’s Missile Tests: What You Need to Know,” CNN, updated December 3, 2017, (accessed June 12, 2020).
  7. David Brunnstrom and James Oliphant, “Trump: North Korea ‘Total Denuclearization’ Started; Officials See No New Moves,” Reuters, June 21, 2018, (accessed June 12, 2020).
  8. Jonathan Cheng, “North Korea Expands Key Missile-Manufacturing Plant, The Wall Street Journal, updated July 1, 2018, (accessed June 12, 2020); Courtney Kube, Ken Dilanian, and Carol E. Lee, “North Korea Has Increased Nuclear Production at Secret Sites, Say U.S. Officials,” NBC News, updated June 30, 2018, (accessed June 12, 2020); 38 North with analysis by Frank V. Pabian, Joseph S. Bermudez Jr., and Jack Liu, “Infrastructure Improvements at North Korea’s Yongbyon Nuclear Research Facility,” 38 North, June 26, 2018, (accessed June 12, 2020); and Ankit Panda, “Exclusive: North Korea Has Continued Ballistic Missile Launcher Production in 2018, Per US Intelligence,” The Diplomat, June 30, 2018, (accessed June 12, 2020).
  9. Daniel R. Coats, Director of National Intelligence, “Worldwide Threat Assessment of the US Intelligence Community,” statement before the Select Committee on Intelligence, U.S. Senate, January 29, 2019, p. 8, (accessed June 12, 2020).
  10. International Crisis Group, “North Korea’s Nuclear and Missile Programs,” Asia Report No. 168, June 18, 2009, (accessed June 12, 2020).
  11. U.S. Department of Defense, Office of the Secretary of Defense, Report to Congress: Military and Security Developments Involving the Democratic People’s Republic of Korea 2017, p. 9, (accessed June 12, 2020).
  12. Bruce Klingner, “Enhance South Korean Military Capabilities Before OPCON Transfer,” Heritage Foundation Backgrounder No. 3452, December 2, 2019,
  13. Jeong Yong-soo and Ser Myo-ja, “Kim Jong-un Ordered a Plan for a 7-Day Asymmetric War: Officials,” Korea JoongAng Daily, January 7, 2015, (accessed June 12, 2020).
  14. North Korea Leadership Watch, “Kim Jong Un Observes and Guides Ballistic Missile Drill,” July 19, 2016, (accessed June 12, 2020); Shin Hyon-hee, “N.K. Says Missile Test Aimed at Ports, Airfields in South Korea,” The Korea Herald, updated July 20, 2016, (accessed June 12, 2020); and North Korea Leadership Watch, “Kim Jong-un Supervises Missile Drill,” March 6, 2017, (accessed June 12, 2020).