International Law and North Korean Nuclear Testing

Christopher J. Le Mon
October 19, 2006

The October 9, 2006 announcement by North Korea (the Democratic People's Republic of Korea, or DPRK) that it had successfully conducted an underground test of a nuclear weapon raises questions about the status of such testing under international law.[1] This Insight examines the international legal norms that could apply to such testing.

Treaties Banning Nuclear Testing

Two treaties restrict nuclear testing as such: the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water (Partial Test Ban Treaty, or PTBT),[2] and the Comprehensive Test Ban Treaty (CTBT),[3] which has not yet entered into force. However, North Korea is not a party to either of these treaties and thus does not have any direct legal obligations thereunder.

Even if the PTBT were considered customary international law,[4] that treaty permits the testing of nuclear weapons underground, so long as radioactive debris is not released outside the territorial limits of the testing state.[5]

Given the recentness of the CTBT and the indications that its drafters viewed the treaty as expanding the law rather than codifying it, its prohibitions on nuclear testing cannot be considered to have attained the status of customary international law. Moreover, several of those states most concerned with the subject matter - namely, states possessing nuclear weapons programs - have not ratified the CTBT, thus weighing against a determination that the prohibition has developed into a rule of customary international law.[6]

The Nuclear Non-Proliferation Treaty (NPT)

North Korea acceded to the NPT in 1985, but in January 2003 announced that it was withdrawing immediately from the treaty[7] and notified the Security Council of its withdrawal. If North Korea were still a party to the NPT, its testing of nuclear weapons would constitute a clear violation of Article II of the treaty, which states that "[e]ach non-nuclear-weapon State

Party to the Treaty undertakes ... not to manufacture or otherwise acquire nuclear weapons or other nuclear explosive devices."

To ascertain whether North Korea could be in violation of its treaty obligations under the NPT,then, a determination must be made as to whether its withdrawal from the treaty was valid. Political considerations have resulted in official ambiguity concerning the status of NorthKorea's treaty obligations under the NPT, and both the United States and the U.N. SecurityCouncil have taken inconsistent views of whether North Korea remains a party to the NPT.[8]

North Korea claimed that its announcement of withdrawal constituted an "automatic andimmediate effectuation of its withdrawal from the NPT." Article X(1) of the NPT allows states parties to withdraw from the treaty and gives them wide, self-judging discretion in doing so, but requires that notice must be given when withdrawing:

Each Party shall in exercising its national sovereignty have the right to withdraw from the Treaty if it decides that extraordinary events, related to the subject matter of this Treaty, have jeopardized the supreme interests of its country. It shall give notice of such withdrawal to all other Parties to the Treaty and to the United Nations Security Council three months in advance. Such notice shall include a statement of the extraordinary events it regards as having jeopardized its supreme interests.

Because Article X(1) of the NPT requires that three months notice be given for withdrawal from the treaty, one must determine whether North Korea's statement that its withdrawal was effectiveimmediately rendered the entire withdrawal ineffective. This must be answered in the negative. As an earlier ASIL Insight concluded:

Noncompliance with the notice requirement does not necessarily mean that the withdrawal from the NPT is invalid. The requirement is couched in terms of a promise to give three months' notice, rather than as a condition that would have to be met in order tomake the withdrawal effective.[9]

With this in mind, one can conclude that the North Korean withdrawal from the NPT likely was legally effective only after the three-month notice period had passed, but not that the failure to give three months' notice made the entire North Korean withdrawal announcement ineffective.

North Korea's Nuclear Disarmament Declaration

As part of the fourth round of Six-Party Talks concerning North Korea's nuclear weapons program, a joint statement from all six countries involved (China, Japan, North Korea, Russia, South Korea, and the United States) was released on September 19, 2005, stating in relevant part that as part of the negotiations, "[t]he DPRK committed to abandoning all nuclear weapons and existing nuclear programs." But does North Korea's having "committed" to this course of action legally obligate it to follow it to completion, and if so, does this commitment include another obligation not to test nuclear weapons?

The International Court of Justice (ICJ) has addressed the issue of legal obligations stemming from unilateral declarations, in the (coincidentally-named) Nuclear Tests case.[10] In its decision, the ICJ concluded that under certain circumstances, a state's unilateral declaration could establish an international legal obligation to abide by the terms of the declaration. The key to the Court's conclusion was the intention of the state making the declaration:

When it is the intention of the State making the declaration that it should become bound according to its terms, that intention confers upon the declaration the character of a legal undertaking, the State being thenceforth legally required to follow a course of conduct consistent with the declaration. An undertaking of this kind, if given publicly, and with the intent to be bound ... is binding.[11]

By the Court's reasoning, then, the two prerequisites for a unilateral declaration to create a binding international obligation are that the declaration (1) be given publicly and (2) be made with the intention of being bound thereby. The International Law Commission has echoed the ICJ's emphasis of these two prerequisites.[12]

Keeping in mind the ICJ's admonition to view the possibility of such obligations according to a "restrictive interpretation,"[13] it is open to question whether the North Korean declaration established a legal obligation not to test a nuclear weapon.[14]

First, the North Korean declaration was not necessarily made as a public statement. Rather, the declaration was made in private negotiations with the other parties to the Six-Party Talks, and then released as part of the Joint Statement. This is more ambiguous than the public announcements by the president of France in the Nuclear Tests case.[15]

Second, the North Korean statement was not necessarily made in such a way to indicate an intent to be bound. The ICJ judgment in the Nuclear Tests case addressed the determination of intention only briefly, stating that "the intention to be bound is to be ascertained by interpretation of the act. When States make statements by which their freedom of action is to be limited, a restrictive interpretation is called for."[16]

In finding that the French declaration at issue in the Nuclear Tests case (which stated that France would halt nuclear testing in the South Pacific) was made with the intention that France would be bound thereby, the ICJ looked to the fact that the statements made by France were unconditional. France's earlier statements had indicated that it would cease testing nuclear weapons "in the normal course of events"; the ICJ reasoned that subsequent unconditional statements constituted a unilateral declaration from which a legal obligation could be derived.[17]

The North Korean statement regarding disarmament does not seem to indicate a similar intention to be bound regardless of the actions of other states. Rather, the commitment was made in the course of negotiations, in which North Korea was expected to give up its nuclear weapons programs in exchange for recognition, an end to international isolation, and other benefits to be provided by the other five parties to talks.[18] This casts the North Korean "commitment" to disarm in a quid pro quo light, making it difficult to argue that this commitment constituted a legal obligation without regard to any action taken by another state.[19]

Going Forward: The Role of the Security Council

Even if the North Korean nuclear test does not violate any positive international law, it would not be outside the scope of regulation by the international legal order. The Security Council has the power to determine whether a situation constitutes a threat to international peace and security, and has wide discretion in making such determinations; in making such a determination, the only Charter limitation on the power of the Security Council is the obligation that it act in accordance with the purposes and principles of the Organization, found in Articles 1 and 2 of the UN Charter.[20] If the Security Council determines that a given situation does constitute a threat to international peace and security, it has the power to order all UNMember States to take action,[21] including by imposing economic sanctions[22] or authorizing the use of force.[23]

To this end, on October 14, 2006 the Security Council unanimously adopted Resolution 1718, invoking Chapter VII of the Charter. The Council demanded that North Korea "return to the [NPT]"[24] and decided that North Korea must abandon its nuclear weapons and nuclear programs,as well as its ballistic missile programs and any other weapons of mass destruction.[25]

Acting explicitly under Article 41, the Council also imposed mandatory sanctions prohibiting all UN Member States from (among other things) directly or indirectly supplying the DPRK with certain armaments, as well as any items or technical assistance that could significantly enhance North Korea's nuclear, ballistic missile, or other weapons of mass destruction programs.[26] The resolution authorized, but did not require, member states to inspect cargo to and from the DPRK, as necessary in order to ensure compliance with the sanctions.[27] In addition, the resolution also ordered Member States to freeze assets owned or controlled by persons or entities engaged in the DPRK's nuclear and ballistic missile programs.[28]





About the author

Christopher J. Le Mon, an ASIL member, is an Associate in the Washington, D.C.

office of Shearman & Sterling LLP, and formerly

served as law clerk to Judges Thomas Buergenthal and Vladlen S. Vereshchetin at

the International Court of Justice.


[1] A previous ASIL Insight examined the international law implications of North Korea's firing of missiles

over the Sea of Japan. See Frederic L. Kirgis, "North Korea's Missile Firings," ASIL Insight, at (July 2006).

[2] Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, Aug. 5, 1963,

480 U.N. Treaty Series (U.N.T.S.) 43.

[3] Comprehensive Nuclear Test-Ban Treaty, opened for signature Sept. 24, 1996, 35 International Legal

Materials (I.L.M.) 1439 (1996).

[4] See Vienna Convention on the Law of Treaties, art. 38, May 23, 1969, 1155 U.N.T.S. 331 (noting the

possibility that rules set forth in treaties may become binding on third states as rules of customary international law).

[5] PTBT, art. 1(b). Although, as noted above, North Korea is not a party to the PTBT, its assertion that no

radioactive leakage had occurred from the testing site might be seen as evidence that it desires to be viewed as in

compliance with this requirement of the PTBT.

[6] See North Sea Continental Shelf (F.R.G./Denmark; F.R.G./Netherlands), 1969 I.C..J. 3, paras. 73-74 (Feb.

20) ("With respect to the other elements usually regarded as necessary before a conventional rule can be considered

to have become a general rule of [customary] international law, it might be that, even without the passage of any

considerable period of time, a very widespread and representative participation in the convention might suffice of

itself, provided it included that of States whose interests were specially affected ?. Although the passage of only a

short period of time is not necessarily, or of itself, a bar to the formation of a new rule of customary international

law on the basis of what was originally a purely conventional rule, an indispensable requirement would be that

within the period in question, short though it might be, State practice, including that of States whose interests are

specially affected, should have been both extensive and virtually uniform in the sense of the provision invoked; and

should moreover have occurred in such a way as to show a general recognition that a rule of law or legal obligation

is involved.").

[7] Treaty on the Non-Proliferation of Nuclear Weapons, July 1, 1968, 729 U.N.T.S. 161.

[8] Pronouncements by the State Department have not been entirely consistent. Compare Sally Horn, "NPT

Article X," Statement to the 2005 Review Conference of the Treaty on the Nonproliferation of Nuclear Weapons, at (Article X "requir[es] three months notice before withdrawal is

complete"), with State Department, Treaties in Force: A List of Treaties and Other International Agreements of the

United States in Force on January 1, 2006, at 486, available at (listing DPRK as party to the NPT).

The Security Council has maintained a similar path of ambiguity. Compare Statement by the President of

the Security Council, U.N. Doc. S/PRST/2006/41 (Oct. 6, 2006) (referring to North Korea's "obligations" under

the NPT and its "announcement of withdrawal" from the NPT rather than an actual, effective withdrawal); S.C. Res.

1695, para. 10 (same), with S.C. Res. 1695, para. 6 (Security Council strongly urges the DPRK to ... return at an

early date to the Treaty on Non-Proliferation of Nuclear Weapons.") (emphasis added). Cf. UN Dep't for

Disarmament Affairs, "Status of Multilateral Arms Regulation and Disarmament Agreements: NPT,"at (in%20alphabetical%20order)?OpenView&Start=1

(not listing North Korea as a party to the NPT).

[9] Frederic L. Kirgis, "ASIL Insight: North Korea's Withdrawal from the Nuclear Nonproliferation Treaty,"

at (Jan. 2003).

[10] Nuclear Tests (Austl. v. Fr.), 1974 I.C.J. 253 (Dec. 20); Nuclear Tests (N.Z. v. Fr.), 1974 I.C.J. 457 (Dec.


[11] Nuclear Tests, para. 46.

[12] International Law Commission, "Guiding Principles applicable to unilateral declarations of States capable

of creating legal obligations," Guiding Principle 1, U.N. Doc. A/61/10, at 367, 368, available at ("Declarations publicly made and

manifesting the will to be bound may have the effect of creating legal obligations.").

[13] Nuclear Tests, para. 47.

[14] Although the Joint Statement was released by all six parties to the talks, it can be considered a declaration

by North Korea to the extent it makes representations on that country's behalf.

[15] Cf. International Law Commission, "Guiding Principles applicable to unilateral declarations of States

capable of creating legal obligations, with commentaries thereto," Guiding Principle 6, U.N. Doc. A/61/10, at 369,

376, available at (noting a rangeof

acceptable audiences depending on the context of the declaration).

[16] Nuclear Tests, para. 47.

[17] Nuclear Tests, para. 44.

[18] Cf. Frontier Dispute (Burkina Faso v. Mali), 1986 I.C.J. 554, para. 40 (Dec. 22) ("to assess the intentions of

the author of a unilateral act, account must be taken of all the factual circumstances in which the act occurred").

[19] As an apagogical hypothetical, one can ask what would be the result if the other five parties chose to

abandon the next round of talks, and withdrew their promised enticements. North Korea, having made its

"commitment" in expectation of benefits to be provided by these countries, can hardly be thought to have had the

intention to unilaterally oblige itself to abandon its nuclear weapons programs if such benefits were withdrawn.

[20] See Christopher J. Le Mon & Rachel S. Taylor, "Security Council Action in the Name of Human Rights:

From Rhodesia to the Congo," 10 U.C. Davis J. Int'l L & Pol. 197, 206-08 (2004), available at (in exercising its responsibilities under Chapter VII, the Security Council is bound

only by the requirement found in Article 24(2) of the Charter that it act according to the purposes and principles of

the United Nations, and by peremptory norms of international law); Christopher J. Le Mon & Rachel S. Taylor,

"Security Council Action in the Name of Human Rights," 11 African Y.B. Int'l L. 263 (2003), available at (same).

[21] UN Charter, art. 25 ("The Members of the United Nations agree to accept and carry out the decisions of the

Security Council in accordance with the present Charter."); cf. Legal Consequences for States of the Continued

Presence of South Africa in Namibia (South-West Africa) notwithstanding Security Council Resolution 276 (1970)

(Advisory Opinion), 1971 I.C.J. 16, para. 116 ("when the Security Council adopts a decision under Article 25 in

accordance with the Charter, it is for member States to comply with that decision, including those members of the

Security Council which voted against it and those Members of the United Nations who are not members of the


[22] UN Charter, art. 41 ("The Security Council may decide what measures not involving the use of armed force

are to be employed to give effect to its decisions, and it may call upon the Members of the United Nations to apply

such measures. These may include complete or partial interruption of economic relations and of rail, sea, air, postal,

telegraphic, radio, and other means of communication, and the severance of diplomatic relations.").

[23] UN Charter, art. 42 ("Should the Security Council consider that measures provided for in Article 41 would

be inadequate or have proved to be inadequate, it may take such action by air, sea, or land forces as may be

necessary to maintain or restore international peace and security. Such action may include demonstrations, blockade,

and other operations by air, sea, or land forces of Members of the United Nations.").

[24] S.C. Res. 1718, para. 4.

[25] S.C. Res. 1718, paras. 5-7.

[26] S.C. Res. 1718, para. 8.

[27] S.C. Res. 1718, para. 8(f).

[28] S.C. Res. 1718, para. 8(d).