How to Increase “Maximum Pressure” on North Korea By Reconsidering Options at Sea

How to Increase “Maximum Pressure” on North Korea By Reconsidering Options at Sea

[Lieutenant Commander Yusuke Saito is a legal advisor in the Japan Maritime Self-Defense Force (JMSDF) and a military professor at Stockton Center for International Law, United States Naval War College. The views expressed in this article are of the author alone and do not necessarily reflect the stance of the U.S. Naval War College and Japan Maritime Self-Defense Force.]


The U.S.–North Korea High Level Meeting scheduled for November 8, 2018 was suddenly postponed. Although the reason for the suspension was unclear, reportedly, North Korea has not been willing to cooperate with the American expectations. While once there was a friendly mood after the historic summit meeting between U.S. President Donald Trump and North Korean leader, Kim Jong-un, on June 12, 2018, concrete achievements are yet to be observed. Rather, in August, the International Atomic Energy Agency (IAEA) reported that North Korea has continued its nuclear program in spite of the Joint Statement with the United States, which pledged complete de-nuclearization of Korean Peninsula.

U.S. President Donald Trump repeatedly insists that the United States will impose and maintain maximum pressure on North Korea. Given this approach, what kind of options do the United States and its partners have to adopt in order to stop North Korea’s seaborne sanctions evasion? This article reviews the current status of such sanctions and explores four options to strengthen them. First, the sanctions should be updated. Second, the wartime right of visit and search may be conducted against with suspending armistice. Third, quarantine as self-defense can be imposed on North Korea. Fourth, ship inspections based on Convention for the Suppression of Unlawful Acts of Violence Against the Safety of Maritime Navigation (SUA Convention) can be considered.

Current Status of Sanctions on North Korea

The UN Security Council adopted thirteen resolutions and four presidential statements. The latest resolution, Resolution 2397 was adopted on December 22, 2017 in response to North Korea’s launch of a Hwasong-15 intercontinental ballistic missile the previous month. Resolution 2397 reaffirms that proliferation of nuclear, chemical and biological weapons, as well as their means of delivery, constitutes a threat to international peace and security. The resolution expresses grave concern at the ballistic missile launch of November 2017. In addition, under Article 41 of Chapter VII of the Charter of the United Nations, the resolution imposes economic sanctions on North Korea, including setting a limitation for the export of crude oil to North Korea and prohibiting the supply and transfer of certain goods. The resolution also references the maritime interdiction operations (MIO) against cargo vessels when appropriate. The resolution states, “Member States shall seize, inspect, and freeze (impound) any vessel in their ports, and may seize, inspect, and freeze (impound) any vessel subject to its jurisdiction in its territorial waters, if [it] has reasonable grounds to believe that the vessel was involved in [illicit] activities… prohibited by resolutions.” The resolution does not authorize MIO on the high seas, however, so the sanctions lack strong enforcement mechanisms. Yet maritime imports play a critical role for the North Korean economy, helping to keep the regime in power. According to a report in the Foreign Policy, the United States informed the U.N. experts that it had taken a dozen satellite images showing 89 tankers unloading suspected illicit cargo into the North Korean ports of Nampo, Najin, and Wonsan between January 1 and May 30, 2018. According to U.S. calculations, those vessels had the capacity to unload nearly 1.4 million barrels of oil, nearly three times the volume allowed under U.N. sanctions. Even if they carried one-third of their load, they would have reached 500,000 barrels – the annual cap imposed on North Korea by UN sanctions. The sanctions could be made more effective through the following measures.

Measures to Strengthen UN Sanctions

There are four possible measures to strengthen the maritime sanctions and better ensure non-proliferation. First, the UN could adopt additional resolutions that authorize Member States to conduct MIO on the high seas. Throughout its history the UN Security Council unambiguously authorized the use of force to conduct MIO in four cases: (1) Res. 221 in 1966 against Southern Rhodesia, (2) Res. 665 in 1990 against Iraq; (3) Res. 787 in 1992 against Bosnia and Herzegovina; and (4) Res. 875 in 1993 against Haiti. Once supported by a UN Security Council resolution, MIO is one of the most legitimate measures to against a recalcitrant state, and presents an opportunity to strengthen the effectiveness of the sanctions regime as a matter of law. Considering the politics within the Security Council, however, this approach might be the most difficult measure to implement, as the acquiescence of all five permanent Members are required. Russia and China have protected North Korea in the past and likely will not approve such an approach. Moreover, Russia and China already have weakened presidential statements in this regard.

A second approach is to conduct “visit and search” of suspected North Korean vessels with the suspension of the 1953 armistice. According to Part Ⅴof the San Remo Manual Applicable to International Conflicts at Sea, in exercising their legal rights in an international armed conflict, belligerent warships and military aircraft have a right to conduct visit and search of foreign-flagged merchant vessels outside neutral waters where there are reasonable grounds for suspecting that they are carrying contraband to aid a belligerent force. Such ships are subject to capture, or even destruction if they fail to yield to visit and search. Whether merchant or otherwise, and regardless of goods or board, enemy vessels may be captured outside neutral waters. Therefore, if U.S. warships were to conduct visit and search of North Korea’s merchant ships, or remarkably, foreign-flagged ships carrying contraband in violation of UN sanctions, the warships of the United States and its partner nations could be authorized to capture those ships without considering jurisdiction of the flag state as a continuation of the UN-authorized defense of the Republic of Korea. The biggest hurdle to overcome for the conduct of visit and search is that it must be executed under only wartime rules. There still exists a state of war on the Korean peninsula, as a peace treaty has not been signed. The armistice between North Korea and the United Nations, signed in 1953, insures “a complete cessation of hostilities and of all acts of armed force in Korea until a final peaceful settlement is achieved.” Therefore, to conduct the visit and search lawfully, the United States and its partner nations would have to suspend the armistice, which has major political ramifications. While MIO might tighten the stranglehold on the North Korean economy, it likely would jeopardize relations with China and Russia, and perhaps other nations, and may result in retaliation by North Korea that overshadows the benefits.

A third possible measure is to quarantine North Korean ships. There is only single case of using quarantine as a peacetime strategy. In 1962 the United States imposed a quarantine against Cuba as an exercise of self-defense during the Cuban Missile Crisis. On October 22 of that year, President John F. Kennedy ordered a naval “quarantine” of Cuba “to defend the United States” by signing Proclamation 3504. The use of “quarantine” is legally distinguished from a blockade, which assumes a state of war. The order of the quarantine indicated that all vessels bound for Cuba were subject to detention and diverted to an American port if they carried nuclear contraband. This measure is seemingly applicable against North Korea to strengthen the effectiveness of sanctions and ensure non-proliferation. In 1962, however, the quarantine was supported by the Organization of American States, but a majority of international law scholars, including Yoram Dinstein[1] and Quincy Wright, concluded that it could not be reconciled with Article 51 of the UN Charter. Thus, applying this to the North Korea case would be difficult to obtain legitimacy.

A fourth option is to conduct visit and search based on the amended SUA Convention. The original SUA Convention was adopted by the IMO in 1985 to impose an obligation to extradite or criminally prosecute suspected crimes at sea. After the interdiction of the M/V Sosan in 2002, however, the SUA Convention was updated, with a new instrument adopted in 2005. Although the interdiction of the ship was successful, in the aftermath of the Sosan MIO, the U.S. and Spanish navies discovered that there was no legal basis to impound the cargo of fifteen Scud missiles from North Korea bound for Yemen. In the aftermath, the SUA Convention was expanded to create additional crimes at sea, including proliferation of missiles and weapons of mass destruction, and their associated materials. Under Article 5(d)-(e), “the requesting Party is granted authorization to board and search the ship, its cargo and persons on board, and to question the persons on board in order to locate and examine documentation of its nationality…” and to determine if an offense has been committed. If there is no response from the flag state within four hours, or some other specific period of time negotiated with the flag state, the boarding may still proceed upon the formation of reasonable suspicion. Therefore, the 2005 SUA Convention allows a requesting state to conduct ship visits with presumed consent from flag states that have joined the convention. These efforts, however, only capture the misuse of foreign-flagged ships on behalf of North Korea and do not apply to North Korean ships, as Pyongyang is not a party to the revised SUA Convention. Diplomatic efforts to push North Korea are easier said than done.

Advantages Disadvantages
UNSC Resolution No doubts on legitimacy Veto from Russia and China
Armistice Suspension Relatively clear legitimacy
Little diplomatic efforts are required for execution.
Breaking a long-standing armistice and potential escalation of tensions
Quarantine Little diplomatic efforts are required for execution. Legitimacy is unclear
SUA Convention No doubts on legitimacy Hard diplomatic efforts for North Korea’s ratification
Only for WMD


There are no great options to strengthen the current economic sanctions and non-proliferation regime against North Korea. Each option has advantages and disadvantages. Yet the United States should at least consider whether these option may form the basis for a hybrid approach as it continues to negotiate with North Korea. For example, if North Korea demonstrates compliance in denuclearization and negotiations show progress, the United States should put the SUA Convention on the table and entice Pyongyang to accept the new regime. If North Korea fails to demonstrate progress or is resistant in negotiations, the United States can continue to push for additional UN Security Council action. Should these efforts fail and North Korea’s nuclear belligerence drives a more dire scenario, the United States and partner nations should consider suspending the armistice or imposing a quarantine before it resorts to the use of force – the high-risk “bloody nose” strategy. Critical elements for future negotiation is that both sides clearly recognize their options. As President Trump has said: “everything is on the table.”

[1] Dinstein, Yoram. War, Aggression and Self-defence. Cambridge: Cambridge University Press, 2017, 226.

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Asia-Pacific, Law of the Sea, Organizations
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