Maintaining stability in Northeast Asia and protecting allies South Korea and Japan are of critical importance to U.S. strategic interests in the Indo-Pacific region. North Korea is threatening those interests by ratcheting up military activity to unprecedented levels, including a record number of missile launches this year as well as highly provocative actions by its ground, air, and naval units near its border with South Korea. Pyongyang is augmenting its military capabilities, particularly tactical nuclear weapons to be deployed with frontline units, to undermine allied deterrence strategies.

Kim Jong-un’s regime has raised tensions to the highest level in years in an attempt to intimidate Washington and Seoul into constraining their military actions. Instead, the allies have resumed large-scale military exercises after a four-year hiatus and reacted strongly to North Korean provocations.

However, the extensive military drills and escalating reactions near and over the inter-Korean border, coming amid threats of preemptive attacks, have created a precarious and potentially unstable situation similar to that of 2017.REF Pyongyang is expected to escalate tensions still further by conducting its seventh overall nuclear test, which would precipitate even more robust allied military responses.

The United States should therefore coordinate closely with South Korea and Japan to enhance deterrence and defense capabilities while being mindful of the increasing danger of inadvertent military clashes on the Korean Peninsula.

Escalating North Korean Missile Threat

In 2022, North Korea has already launched over 70 ballistic missiles—all violations of U.N. resolutions—and eight cruise missiles. This is exponentially higher than the previous annual record of 26 missile launches in 2019.

This year’s launches have included a hypersonic glide vehicle with a maneuverable warhead that is capable of evading allied missile defenses; a long-range strategic cruise missile; the first intercontinental ballistic missile (ICBM) launches since 2017; the first intermediate-range missile flight over Japan since 2017; and the first underwater missile launch from a lake.

Pyongyang has demonstrated its enhanced missile capabilities with the longest flight by a North Korean cruise missile (2,000 km, which is sufficient to target most of Japan); its longest ballistic missile flight (4,500 km, the distance to U.S. military bases in Okinawa); and a Hwasong-15 ICBM flown on a lofted trajectory to a greater height than its previous launch in 2017. Pyongyang also unsuccessfully tested its new multiple-warhead Hwasong-17 ICBM. In addition, the regime paraded a new Pukguksong-6 submarine-launched ballistic missile (SLBM) that is even larger than previous models, but it has not yet conducted a flight test.

North Korea’s blitz of 13 missile launches during a two-week period in September and October demonstrated that the regime has progressed from developmental testing of new missiles to exercising its tactical nuclear missile units to assess their operational readiness. Pyongyang announced that the launches simulated tactical nuclear attacks on South Korean ports, airfields, and hardened military command targets,REF similar to exercises in 2016–2017 that simulated attacks on South Korean and Japanese targets.

On November 1, Pyongyang launched 23 ballistic and surface-to-air missiles, the highest number of launches ever conducted in one day and from the largest number of different launch sites located throughout the country. One of the ballistic missiles landed less than 40 miles off South Korea’s coast, outside of territorial waters but the first North Korean missile ever flown south of the inter-Korean maritime boundary.

The increasing rate and diversity of missile launches shows that North Korea is making significant progress toward implementing a more capable and flexible nuclear strategy that includes preemptive strikes with strategic, tactical, and battlefield nuclear weapons.

New Basing Mode. In September, North Korea announced that it had conducted a missile drill simulating “loading tactical nuclear warheads at a silo under a reservoir.”REF It is unclear whether the regime intends a permanent silo built under the lake or a mobile submerged test barge similar to those used for early tests of new SLBMs off North Korea’s east coast.

A fixed underwater silo would involve a complicated engineering process and presumably would be detected by U.S. intelligence satellites. A mobile submerged launch platform could be more cost-effective, survivable, and difficult to detect than a missile-carrying submarine. Either system would further diversify potential North Korean nuclear missile launch sites beyond existing road-mobile and train-based launchers.

Provocative Military Actions

In October, North Korean air, ground, and naval forces conducted significant military operations close to South Korea, many on a scale never seen before.

North Korea twice conducted rare air-attack drills close to the Demilitarized Zone (DMZ) though north of the no-fly zone agreed to in the 2018 inter-Korean Comprehensive Military Agreement (CMA). Pyongyang announced that the exercise simulated an attack on an enemy military base utilizing “air-to-surface medium-range guided bombs and cruise missiles.”REF Two days later, South Korea detected a flight of 10 North Korean aircraft just 15 miles north of the border and seven miles north of the maritime boundary in the Yellow Sea.REF

North Korea carried out a large-scale bombing and air-to-air attack drill in which more than 150 fighter planes “took off simultaneously for the first time in history.”REF Three weeks later, North Korea claimed that it conducted an air exercise with 500 aircraft, but the South Korean military reported only 180 aircraft near the DMZ.

During several large-scale exercises in October and November, North Korean ground forces cumulatively fired over a thousand artillery rounds into waters off both its east and west coasts. The shells landed in the maritime buffer areas near the border in violation of the CMA. Pyongyang indicated that one of the drills simulated an attack on a South Korean airfield.REF

In late October, North and South Korean naval forces exchanged warning shots off the west coast. A North Korean freighter strayed south of the Northern Limit Line (NLL). South Korea responded with 20 machine gun rounds, and North Korea later fired 10 multiple rocket rounds into the maritime buffer zone, again violating the CMA.

The NLL has served as de facto inter-Korean maritime boundary since the end of the Korean War in 1953, although it has been disputed by North Korea in recent years. The area has been the site of several deadly inter-Korean naval clashes in 1999, 2002, and 2009, as well as the North Korean sinking of the South Korean naval ship Cheonan in 2010 and shelling of South Korea’s Yeonpyeong Island in 2010.

North Korea’s Objectives

North Korea’s escalating military provocations are the result of its decades-long campaign to develop a nuclear warfighting capability and its exploitation of recent circumstances, including allied resumption of large-scale military exercises, the diversion of international attention by Russia’s invasion of Ukraine, and deteriorating U.S. relations with China and Russia.

Pyongyang is seeking to gain tacit acceptance of its violations of U.N. resolutions through routinization of its missile launches and reliance on Chinese and Russian obstructionism at the U.N. Security Council to prevent additional punitive measures.REF In the past, Beijing and Moscow grudgingly allowed the adoption of incrementally stronger U.N. resolutions in response to such egregious North Korean violations as nuclear or ICBM tests. This year, however, both countries have repeatedly rejected U.S. efforts to punish North Korea for repeated violations of U.N. resolutions.

By depicting its military provocations as responses to resumed U.S.–South Korean military drills, Pyongyang seeks to coerce the allies into curtailing future exercises. The regime may also be challenging the legitimacy of the disputed inter-Korean maritime boundary and attempting to push it further south.

Strong Allied Responses

North Korea has often used provocations and threats to drive a wedge between the United States and its allies. However, its recent behavior has instead led to a firmer allied military posture. Under President Yoon Suk Yeol, South Korea is now willing to respond to North Korean provocations with displays of military strength. Yoon also has accepted the Biden Administration’s request to resume the scope and scale of combined military exercises and rotational deployments of U.S. strategic assets, both of which were cancelled by President Donald Trump in 2018.

Resumption of Large-Scale Exercises. In late September, Washington deployed the USS Ronald Reagan to the Sea of Japan for naval exercises with South Korea for the first time in five years. That exercise was followed by trilateral anti-submarine drills with South Korean and Japanese ships—also the first in five years—that included a scenario against the launching of a North Korean SLBM.REF The U.S., South Korean, and Japanese navies also conducted trilateral naval missile defense exercises to detect, track, and intercept ballistic missiles.REF

In mid-October, South Korea conducted its large-scale Hoguk exercise involving naval, army, air force, and Marine units. The exercise involved Aegis destroyers, frigates, Apache helicopters, F-15K and KF-16 fighters, U.S. Apache helicopters, and A-10 attack aircraft.REF The South Korean Marine Corps subsequently conducted amphibious landing drills that involved 6,000 Marine and naval personnel, amphibious vehicles, assault ships, and 50 aircraft and helicopters.REF

From October 31 to November 5, the U.S. and South Korea conducted their largest-ever Vigilant Storm (formerly Vigilant Ace) combined air exercise. The exercise, the first in five years, involved 140 South Korean aircraft and 100 U.S. aircraft flying 1,600 sorties, the highest ever for the annual exercise.REF The U.S. included four B-1 bombers in the exercise for the first time since 2017.

Reaction to North Korean Provocations. South Korea scrambled fighter jets several times when North Korean air exercises approached the inter-Korean border. After North Korea’s missile flight over Japan, U.S. and South Korean fighter jets conducted a precision bombing drill with ATACM and Hyunmoo-2C short-range ballistic missiles against a target off the west coast, and the two militaries fired five surface-to-surface missiles into the Sea of Japan. U.S. and Japanese fighter aircraft also conducted combined flying exercises over the Sea of Japan.REF

Preparing for Another Nuclear Test

By November, Pyongyang described the situation on the Korean Peninsula as having entered the “serious confrontation stage” and warned that it could take “more powerful follow-up measures.”REF North Korea could conduct its first nuclear test in five years, an ICBM flight over Japan, or tests of several new SLBMs.

It is expected that the next nuclear test will be of a new generation of smaller, low-yield tactical nuclear weapons. The test would be much smaller than the massive 250 kiloton test of a hydrogen bomb in 2017. The testing of a small tactical warhead for battlefield use would exponentially increase the threat to South Korea and Japan as well as to U.S. forces stationed there.

The U.S., South Korea, and Japan have announced that they would respond at an “unparalleled” scale to another nuclear test.REF Possible allied responses include increased rotational deployment of U.S. strategic assets including bombers, submarines, dual-capable aircraft, and carrier strike groups; extensive allied military exercises; imposition of new sanctions against North Korean entities; and greater trilateral security cooperation among Seoul, Tokyo, and Washington.

North Korea would likely react with additional military actions, which would trigger further allied actions. During the currently escalated tensions, Pyongyang might misconstrue allied military exercises or responses to regime provocations as a prelude to an actual attack. Pyongyang might rush to preempt the perceived preemption, which could lead to major conflict.

On September 8, 2022, Pyongyang passed a new law that lowered the threshold for its use of nuclear weapons.REF The regime declared that it would use nuclear weapons in response to or perceived preparations for a U.S. or South Korean nuclear or non-nuclear attack on regime leadership, nuclear command structure, or important strategic targets. In early November, the regime threatened that any military action against North Korea would trigger a nuclear response and that the U.S. and South Korea would “pay the most horrible price in history.”REF

What the United States Should Do

As noted, maintaining stability in Northeast Asia and protecting South Korea and Japan in the face of escalating North Korean provocations are of critical importance to U.S. strategic interests in the Indo-Pacific region. Washington should therefore:

• Respond proportionally to North Korean provocations. Pyongyang’s threatening military actions should be met with sufficient allied reaction to demonstrate resolve. However, such responses should be calibrated to reduce the likelihood of North Korea’s misinterpreting them as the initiation of a preemptive attack.
• Propose tension-reduction talks. The current cycle of recurrent military responses and counter-responses has escalated tensions and the potential for unintended armed conflict. The U.S. and South Korea should press for discussions of tension-reduction measures, such as prior notification of large-scale military movement or exercises, limits on military activity near the DMZ, and verification protocols. Unfortunately, Pyongyang’s violation of previous agreements and rejection of diplomatic dialogue does not bode well for such an initiative.
• Enhance the scope and pace of combined military exercises. Four years of cancelled, reduced, and constrained allied military exercises did not induce North Korea either to moderate its nuclear or missile programs or to reduce its own military exercises. The U.S. and its allies must reject North Korean intimidation efforts and instead restore military exercises and the rotation of U.S. strategic assets to pre-2018 levels in order to enhance deterrence and defense against the growing North Korean threat.
• Augment allied missile defenses. North Korea’s growing ICBM threat to the American homeland requires that Washington maintain plans to augment missile defense to 64 ground-based interceptors. South Korea should continue deployment of its medium-range and long-range surface-to-air missile systems as well as the planned acquisition of SM-6 missiles for its Aegis-equipped naval ships.
• Enhance extended deterrence guarantee to allies. South Korea and Japan question the viability of the U.S. commitment to their defense both because of Pyongyang’s increasing ability to target the United States with nuclear weapons and because of previous U.S. threats to remove forces from the region. The recently restored U.S.–South Korean Extended Deterrence Strategy and Consultation Group could discuss potential initiatives such as establishing a bilateral (or trilateral with Japan) Nuclear Planning Group to increase transparency and coordination on nuclear strategy, planning, targeting, and exercises. Washington could also assess a schedule for the increased rotation of strategic assets to South Korea. However, the U.S. should push back on growing advocacy for:
  1. The return of U.S. tactical nuclear weapons to the Korean Peninsula,
  2. Development of an indigenous South Korean nuclear weapons program,REF
  3. A U.S.–South Korea nuclear-sharing agreement, and
  4. Abandonment of denuclearization as a negotiating objective.REF

Conclusion

North Korea’s missile launches show that the regime has both enhanced the quality and quantity of its nuclear-capable missile systems and improved the survivability of its nuclear missile force. This not only increases the threat to the United States, South Korea, and Japan, but also risks degrading allied missile defenses and deterrence strategies.

Kim Jong-un’s willingness to resume missile flights over Japan and ICBM launches, initiation of extensive military exercises, and increased provocations close to the inter-Korean border all exacerbate regional tensions and risk triggering a military crisis. Washington and Seoul must respond resolutely to North Korean incitements while simultaneously seeking ways to reduce the potential for stumbling into war.

Bruce Klingner is Senior Research Fellow for Northeast Asia in the Asian Studies Center at The Heritage Foundation.