As President Obama travels to South Korea for next week’s nuclear summit, North Korea’s threat to launch a missile in mid-April will overshadow the gathering of world leaders. The United States and South Korea should work the room to prepare a strong international response to yet another North Korean violation of U.N. resolutions. China will resist a stern U.N. Security Council response, but Washington and Seoul must make clear that Pyongyang’s increasingly dangerous actions and commensurately stronger allied responses are due partly to Beijing’s timid efforts to control its belligerent ally.

But there is another important Korean missile issue that merits President Obama’s attention: accepting Seoul’s entreaty to remove U.S. restrictions on South Korea’s ballistic missiles. At present, under the terms of a bilateral agreement with the United States, Seoul is precluded from developing any ballistic missile with a range greater than 300 kilometers (186 miles). The only way for South Korea to reach North Korean targets in the rear areas—including some of Pyongyang’s 700 Scud missiles—with ballistic missiles would be to place them along the demilitarized zone, well within range of North Korea’s artillery.

Seoul’s voluntary self-restriction did not prevent North Korea from developing missiles that can reach all of South Korea. America’s critical ally should be allowed to extend its missile range to 800 km (approximately the length of the Korean Peninsula) so it can have a sufficiently robust indigenous military to deter, defend, and defeat North Korean hostile actions, including a ballistic missile attack. The need is particularly acute given North Korea’s two attacks on South Korea in 2010 and Seoul’s gaining wartime operational command of its military from the United Nations Command in 2015.

Enabling an Ally to Protect Itself  

In 1979, South Korea signed an agreement with the United States to limit its ballistic missile capabilities to a 180 km (112 mile) range and 500 kilogram payload. In 2001, the U.S. and South Korea modified the agreement to allow Seoul to develop missiles to the export limit of the Missile Technology Control Regime (MTCR): i.e., a range of 300 km (186 miles) with a 500 kilogram payload.

The MTCR is a voluntary arrangement among countries to control the export of ballistic missiles (and their components) capable of delivering weapons of mass destruction. The only specific restriction in the MTCR is a prohibition on the transfer of missile production technologies. The agreement permits cooperation among member countries, including missile transfers, as long as the recipient country pledges not to modify any transferred systems to deliver weapons of mass destruction.

North Korean Threats and Attacks  

North Korea has 700 Scud short-range tactical ballistic missiles that can strike South Korea. The Scud missile has a conventional explosive warhead, but it could carry chemical or biological warfare agents. Pyongyang could utilize Scud missiles to fire non-persistent chemicals at frontline units and persistent chemicals against rear logistical and resupply targets, such as Busan Harbor.

North Korea also has 300 No-Dong missiles targeting Japan and 100 to 200 Musudan missiles that can reach U.S. bases in Okinawa and Guam. In January 2011, Secretary of Defense Robert Gates warned that “North Korea is becoming a direct threat to the United States” since, within five years, North Korea could develop an intercontinental ballistic missile. In 2009, North Korea launched a Taepo Dong-2 missile to a range of 2,500 miles. Although the missile’s third stage failed, it demonstrated a long-range capability that puts Alaska, Hawaii, and the western United States at risk.

Pyongyang announced on March 16 that it would conduct a “satellite launch” during April 12–15. U.N. Security Council Resolution 1874 precludes North Korea from any launch utilizing “ballistic missile technology.”

In 2010, Pyongyang conducted two unprovoked acts of war against South Korea: sinking a South Korean naval ship and shelling a civilian-inhabited island. The attacks were a deadly reminder of the threat from North Korea’s conventional forces and Pyongyang’s willingness to use them.

Director of U.S. National Intelligence James Clapper warned after Pyongyang’s sinking of the South Korean ship that it portended “a dangerous new period when North Korea will once again attempt to advance its internal and external political goals through direct attacks on our allies in the Republic of Korea.”

A Comprehensive Security Strategy  

The North Korean attacks led to a comprehensive review of South Korean defense requirements. Seoul identified numerous measures to improve the military’s ability to detect and defeat North Korean provocations.

A South Korean presidential committee on military reform recommended in 2011 that Seoul should change from passive defense to proactive deterrence, including preemptive strikes on North Korean bases upon detection of impending nuclear or missile attack. South Korea’s military strategy was “based on the idea that the North would not attack, as long as we built up our forces, but the [naval attack] showed this concept to be unsuitable.”

The head of the presidential committee recommended that South Korea acquire weapons capable of attacking North Korean weapons of mass destruction, since South Korea “can prevent the North’s military superiority only when it has the nonnuclear precision strike capabilities that could incapacitate its WMDs before they are put to use.”

Along with these measures, South Korea should also augment its missile defense system. During 10 years of liberal South Korean administrations, Seoul was reluctant to take any measures that would aggravate North Korea or China, including purchasing sufficient missile defense systems or integrating them with a comprehensive regional network with the United States and Japan. Seoul developed an independent lower-tier system of PAC-2 and SM-2 missiles.

Although President Lee Myung-bak expressed greater interest in improving South Korea’s missile defenses, the country has not made sufficient progress. A comprehensive

South Korean military comprised of an integrated network of modern conventional forces, missile defenses, and augmented power projection capabilities would improve the country’s security.

Increasing Allied Security  

On the eve of President Obama’s arrival, President Lee Myung-bak told journalists that the 300 kilometer limit “was set many years ago on the assumption fighting would happen around the demilitarized zone…. [South Korea now faces] new needs in its defense environment [since] North Korea has missiles and long range artillery that can reach all the way down to Jeju Island. South Korea is in need of expanding its defense posture in case of any contingencies.”

North Korea may choose in the future to use or threaten to use Scud missiles to pressure Seoul. An inability to defend against the North Korean missile threat would leave South Korea more susceptible to North Korean influence. To counter this threat, Seoul should be allowed to extend its ballistic missile range. Doing so would augment a comprehensive array of South Korean and allied security capabilities to deter and, if necessary, defeat North Korean coercive diplomacy and military attacks.

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