On July 4 and 5, 2006, the Democratic People's Republic of Korea (North Korea) test-fired seven unarmed missiles over the Sea of Japan. One of them was a long-range missile, the Taepodong 2, which exploded and fell into the sea before it could complete its test flight. If it had not gone down prematurely it is possible that it would have entered the airspace of Japan. The United States, Japan and several other nations objected to the test firings and have sought a strong response from the U.N. Security Council, but apparently have not asserted that the firings violated international law.
The customary international law principle of respect for territorial sovereignty prohibits a nation-state's unauthorized use of the air space above another nation-state's territory. Thus if the North Korean long-range missile had entered Japanese air space, there would have been a violation of international law - even if no physical damage had been done to Japan. But since all of the missiles wound up in the Sea of Japan outside Japanese territorial waters, there would be no violation of Japanese territorial sovereignty.
It would be a stretch to argue that customary international law prohibits the testing of unarmed missiles over the oceans, unless ships at sea or other lawful users of ocean space or air space are harmed. Customary international law reflects the practice of nation-states, and that practice for many years has encompassed missile testing over the high seas by the United States and others (most recently, by India). The practice has usually been justified as necessary in order to be prepared for self-defense if an attack on the testing state were to occur. North Korea has apparently made that argument regarding its current tests. Nevertheless, it could be argued that North Korea violated a procedural norm of international law by failing to give prior notice of its intent to test the missiles, thus unnecessarily endangering ships or aircraft that might unknowingly be in the missiles' path.
The various multilateral arms control treaties do not prohibit the testing of unarmed missiles. The U.N. Convention on the Law of the Sea, however, contains some potentially relevant provisions. North Korea is not a party to the Convention, but the basic provisions in it relating to the high seas are widely acknowledged to reflect custom. The Convention recognizes the "freedom of overflight" above the high seas, without elaboration. But it also says, "The high seas shall be reserved for peaceful purposes." On its face, that might be read to preclude military activities on or above the high seas, but another provision in the Convention clearly contemplates the use of the high seas by warships. Warships routinely traverse the high seas. When the Convention was being negotiated, the United States made its position clear that "peaceful purposes" did not preclude military activities generally.
In 1999, after negotiations with the United States, North Korea agreed to a moratorium on missile launching pending further talks on banning the testing, production and export of long-range North Korean missiles. Those talks apparently have not been held since 2000. In 2002, though, the North Korean leader and the Prime Minister of Japan agreed to the
Neither the 1999 agreement nor the 2002 Pyongyang declaration was formalized as a treaty. Nevertheless, some non-treaty declarations have been treated as binding under international law. In 1974 the International Court of Justice treated as binding a unilateral public declaration by the French government to the effect that no further French nuclear tests would be held in the atmosphere. The Court pointed out that other States might rely on such a declaration, but it did not condition its decision on any actual reliance. It did condition its decision on an intent by the State to be bound by its declaration, but it was able to infer such an intent under the circumstances of that case.
The International Law Commission, a U.N. body consisting of 34 international law experts from 34 countries, has undertaken a study of the legal effect of unilateral acts of States. The Commission's rapporteur, Víctor Rogríguez Cedeño, has considered several unilateral governmental statements, including the French statements on nuclear tests and statements in 1995 by China, France, Russia, the United Kingdom and the United States to the effect that they would not use nuclear weapons against any non-nuclear party to the Treaty on the Nonproliferation of Nuclear Weapons, except in self-defense under certain narrowly-defined circumstances. The rapporteur concluded that the 1995 statements "are mainly political statements which are not legally binding upon their authors."
North Korea has asserted that it is not legally bound by the Pyongyang declaration or by any other statements it may have made. A moratorium by definition is a suspension or delay rather than a termination, and in this case it was a suspension of indefinite duration. Consequently, even if the declaration was initially intended to be legally binding, North Korea could argue that by its nature it could be withdrawn after some passage of time. Since neither the United States nor any of the other States objecting to the North Korean tests have claimed that the tests violated international law, they seem to have acquiesced in the North Korean assertion that its declaration is not now legally binding. The U.N. Security Council, in its resolution condemning North Korea's missile launches, expressed its "profound concern" at North Korea's "breaking of its pledge to maintain its moratorium on missile launching," but did not assert that North Korea had violated international law.
Even if the missile test flights did not violate international law, they could still be considered a threat to international peace and security under Chapter VII of the U.N. Charter. If the U.N. Security Council were to consider them so, it could adopt a resolution imposing diplomatic, economic or even military sanctions on North Korea. Such a resolution, if adopted, would be legally binding on all U.N. member States.
In its actual resolution, however, the Security Council did not quite say that the test flights were a threat to international peace and security, and did not expressly invoke Chapter VII of the Charter. Instead, the Council "affirmed" that "such launches jeopardize peace, stability and security in the region, particularly in light of [North Korea's] claim that it has developed nuclear weapons." The Council then said that it was "acting under its special responsibility for the maintenance of international peace and security." It condemned the launches and demanded that North Korea suspend all activities related to its ballistic missile program. The Security Council resolution also "requires" all U.N. member states to exercise vigilance and prevent transfer to or from North Korea of missiles or missile-related items (including technology).
Even though the Security Council did not expressly act under Chapter VII of the Charter, it could - and probably did - impose legally binding obligations on North Korea and other U.N. member states under other provisions in the Charter. Article 24, which is not in Chapter VII, confers on the Security Council "primary responsibility for the maintenance of international peace and security" - which is just what the Council said it was doing in the preamble to its resolution, quoted above. Article 25 says that the members of the U.N. "agree to accept and carry out the decisions of the Security Council in accordance with the present Charter." In a 1971 Advisory Opinion on the legal consequences for states of South Africa's then-presence in Namibia, the International Court of Justice said that the Council could and did rely on Article 24 when it adopted a resolution in the exercise of its responsibility to maintain international peace and security, declaring South Africa's presence in Namibia illegal and calling on all states to refrain from any dealings with the South African government concerning Namibia. According to the Court, such a resolution, if intended to be a "decision," is binding on all U.N. member states under Article 25. When the Security Council, in the current resolution, demanded that North Korea suspend its ballistic missile activities and required all member states not to transfer missiles or missile-related items to or from North Korea, it sounded very much as though it was making a decision.
Frederic L. Kirgis, an ASIL member, is Law School Association Alumni Professor Emeritus at the Washington and Lee University School of Law. He has written books and articles on international law, and is an Honorary Editor of the American Journal of International Law. The author is grateful to Charlotte Ku for reviewing a draft of this Insight. Any errors or omissions are the author's own.
 N.Y. Times, July 7, 2006, p. A12.
 Case Concerning Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States), 1986 I.C.J. 14, paragraph 251, reprinted in 25 International Legal Materials (I.L.M.) 1023 (1986); see also I.H.Ph. Diederiks-Verschoor, An Introduction to Air Law 12-13 (7th rev. ed. 2001).
 The U.N. Security Council, in a resolution condemning the missile launches, expressed its "concern" over North Korea's failure to give adequate notice. S.C. Res. 1695, preamble (15 July 2006). On the arguable duty to give prior notification, see Kirgis, Prior Consultation in International Law: A Study of State Practice 360-361 (1983).
 U.N. Convention on the Law of the Sea, 10 Dec. 1982, art. 87, 1833 U.N. Treaty Series 3.
 Id. art. 88.
 Id. art 95 ("Warships on the high seas have complete immunity from the jurisdiction of any State other than the flag State.")
 See Satya N. Nandan C.B.E. & Shabtai Rosenne (eds.), United Nations Convention on the Law of the Sea, 1982: A Commentary, vol. III, at 89 (1995).
 International Herald-Tribune, June 20, 2006.
 Nuclear Tests Cases (Australia and New Zealand v. France), 1974 I.C.J. 253.
 U.N. Doc. A/CN.4/557, at 21 (2005).
 MSNBC, supra note 8.
 The Vienna Convention on the Law of Treaties, Article 56, contemplates withdrawal from legally binding treaties if "it is established that the parties intended to admit the possibility of denunciation or withdrawal," or if such a right "may be implied by the nature of the treaty."
 S.C. Res. 1695, preamble, supra note 3.
 Id., preamble and operative paragraphs 1-4.
 Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) Notwithstanding Security Council Resolution 276 (1970), 1971 I.C.J. 16, paragraphs 110-115, reprinted in 10 I.L.M. 677 (1971).
 By way of contrast, some other language in the resolution sounds precatory. For example, the Council "strongly urged" North Korea to return immediately to the six-party talks on its nuclear program.