North Korea announced on January 4 that it had conducted a successful H-bomb nuclear test of a miniaturized warhead.[1] Prior to the announcement, sensors had detected a 5.1 magnitude seismic event at the same approximate location as North Korea’s 2013 nuclear test. Nuclear experts are continuing to analyze the data, but preliminary assessments are that North Korea did indeed conduct its fourth nuclear test. South Korea has convened an emergency cabinet meeting to consider its response.

Seismologists can distinguish between natural earthquakes and man-made explosions since each has distinctive characteristics. The South Korean meteorological administration stated, “Considering the waveform and the amplitude of the earthquake, it seems certain that it was an artificial quake. [There is] the high possibility of it being a nuke test.”[2] An estimated size of the explosion has not been determined nor have radioactive isotopes—which would confirm a nuclear explosion—yet been detected.

Satellite imagery had shown excavation and preparatory activity at the Punggye-ri Nuclear Test Site during the past two years. However, no indications of an imminent nuclear test were detected prior to the explosion. North Korean leader Kim Jong-un asserted last month that his country had built a hydrogen nuclear bomb to “defend its sovereignty and the dignity of the nation.”[3] Kim’s initial assertion about hydrogen bombs was met with expert skepticism, and it may be more likely that Pyongyang has achieved a boosted fission rather than a fusion bomb.[4] Such a weapon would be larger than Pyongyang's first three nuclear tests (and the 1945 U.S. atomic weapons) but not of the magnitude of a hydrogen fusion bomb.

If confirmed, North Korea’s fourth nuclear test, particularly of an improved weapon, is a dangerous development. With its ongoing development of several different missile systems, North Korea poses an increasing direct threat to the United States, South Korea, and Japan. Experts estimate that Pyongyang currently has 10–16 nuclear weapons, with the potential to increase that cache to as many as 50–100 by 2020.[5] North Korea has likely already achieved warhead miniaturization, the ability to place nuclear weapons on its medium-range missiles, and a preliminary ability to reach the continental U.S. with a missile.[6]

What Washington Should Do

Washington should be consulting with Seoul and Tokyo to devise a common response to the North Korean nuclear test. The allied response should include:

• Convening the U.N. Security Council to implement a new resolution to impose strong punitive sanctions as well as to close loopholes, such as Article 42 of Chapter VII of the U.N. Charter, which allows for enforcement by military means. This would authorize naval ships to intercept, board, and inspect North Korean ships suspected of transporting prohibited nuclear, missile, and conventional arms, components, or technology.
• Calling upon all U.N. member nations to fully implement existing U.N. resolution requirements to prevent North Korea’s procurement and export of missile-related and WMD-related items and technology, as well as freeze the financial assets of any involved North Korean or foreign person, company, or government entity. Any violating government, business, bank, or individual should be subject to sanctions.
• Adopting a more comprehensive list of prohibited items and materials. The U.N. Experts Group identified several items and materials critical to Pyongyang’s nuclear programs that should be—but have not been—added to the list of products banned for transfer to North Korea.
• Publicly identifying and sanctioning all foreign companies, financial institutions, and governments assisting North Korea’s nuclear and missile programs. The U.N. and U.S. should target financial and regulatory measures against any entity suspected of aiding or abetting North Korean nuclear, missile, and conventional arms development; criminal activities; money laundering; or import of luxury goods.
• Imposing third-party sanctions. The U.S. should penalize entities, particularly Chinese financial institutions and businesses, that trade with those on the sanctions list or export prohibited items. The U.S. should also ban financial institutions that conduct business with North Korean violators from access to the U.S. financial network.
• Augmenting U.S. sanctions.[7] President Obama’s assertion that North Korea is the most heavily sanctioned country in the world is simply not true. Washington has targeted fewer North Korean entities than those in the Balkans, Burma, Cuba, Iran, and Zimbabwe.[8] The U.S. has targeted more than twice as many Zimbabwean entities than North Korean. Nor has Washington designated North Korea as a primary money-laundering concern as it has Iran and Burma.

For its part, South Korea should:

• Resume propaganda broadcasts along the demilitarized zone, dramatically increasing broadcasting into North Korea. These efforts should include assessing the viability of using drones along North Korean coasts and removing any restrictions on nongovernment organizations sending information leaflets via balloons into North Korea. The August land mine crisis showed the sensitivity of the Kim Jong-un regime to psychological operations.
• Sever its involvement in the Kaesong industrial park. The joint business venture was always more focused on political than economic objectives. Since its inception, the Kaesong venture failed to achieve its primary objective of inducing economic and political reform in North Korea and moderating the regime’s belligerent foreign policy.
• Request U.S. deployment of the terminal high altitude air defense missile defense system. South Korea’s indigenous missile defense system is insufficient to defend against North Korea’s growing nuclear and missile threat.[9]

Conclusion

North Korea’s nuclear test is a flagrant violation of numerous U.N. Security Council resolutions. It reflects Pyongyang’s continued pursuit of its prohibited nuclear weapons programs in open defiance of the international community despite countless attempts by the U.S. and its allies to reach a diplomatic resolution. The regime has repeatedly asserted it has no intention of ever abandoning its nuclear weapons, even revising its constitution to enshrine itself as a nuclear weapons state. North Korea’s continuing improvement and augmentation of its nuclear arsenal threatens the U.S. and its allies. It is time for the Obama Administration to abandon its policy of timid incrementalism and fully implement existing U.S. laws by imposing stronger sanctions on North Korea and to work with Congress to determine additional measures.