Countries have have national airspace above their territory and permission must be granted (by the relevant national aviation authority/government), however there is debate about how high this extends.

North Korea have recently threatened to fire missiles towards Guam, which would fly over Japanese territory, so what are the political and legal aspects to this?

Are there agreement between nations about missile launches, especially defensive missile systems?

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    There's a difference between "legal" and "conforming to treaties" and "accepted as casus belli but not per se illegal" and "Bad JuJu"
    – user4012
    Aug 10, 2017 at 16:54
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    Why would it be different if it is an ICBM than if it is an airplane or a man thrown by the world's biggest slingshot? Either it violates another country's airspace or it does not. The reason of the violation and the kind of vehicle may be relevant to the country whose airspace was violated in order to decide how to react, but not to the fact that its sovereignty was attacked.
    – SJuan76
    Aug 10, 2017 at 18:49
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    @SJuan76 - sometimes there are agreed upon protocols or prohibitions on the use of specific items/technologies or using them in certain ways. So, possibly an ICBM is not only violating airspace, but is prohibited to be used by treaty or convention, because they are ICBMs. Or, to my question, if the use of an ICMB would be banned, would it be if used to launch out of sovereign airspace, or would I be also banned from use within my borders, as well? A lot of ways to violate conventions. Thanks, DClayton, for clarifying what is germane to the question. Aug 10, 2017 at 19:44
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    There is no such thing as "legal" or "illegal" when it comes to countries. Any law is only as strong as your capability to enforce and when it comes to countries as a whole everything depends on the goodwill of the leaders, unless you're willing to wage war against them. Aug 12, 2017 at 22:54

3 Answers 3


Ultimately, framing this as a legal question rather than as a political one is only marginally useful. There is no court which could hold North Korea accountable for a violation of an international legal obligation or a treaty violation. And, seeking recourse from the domestic courts of North Korea in the context of its current totalitarian regime would be futile.

  • Protocol I to the Geneva Conventions (to which North Korea is a party) bans the used of nuclear weapons on civilian targets.

None of the other treaties to which North Korea is a party, other than its membership in the United Nations which calls for peaceable resolution of disputes and the involvement of the U.N. Security Council, are plausibly relevant to this situation.

  • Firing an ICBM over a nation is a violation of its airspace under general principles of international law. Both Japan and the U.S. would be aggrieved.

  • Directing an ICBM at or over another sovereign nation's territory, even if it is intended as a warning shot or a way of demonstrating a credible threat, could be determined by the offended countries to be an act of war that would justify declaring all out war on the offending country. The U.S., Japan, and any of their respective allies could join this cause if they saw fit based upon a threat directed at any one of them.

In practice, since any recourse for violating international law or a treaty would involve action organized by the aggrieved country rather than legal action, the real question is whether Russia or China would stand in the way of actions by the U.S., Japan and their allies to retaliate against North Korea. And, the main relevance of international law and treaties would be to provide China and Russia with justification for not intervening and to provide allies with a justification for intervening.

China accounts for 75% of North Korea's trade, borders North Korea, and has stronger relations with it than any other country, while North Korea is currently fairly peripheral in Russia's political calculus. Therefore, the primary issue, which is really only tangentially related to any argument related to legality, is whether China would take any action to interfere with or object to military action and/or sanctions directed by the U.S. and/or Japan and/or their allies against North Korea, and whether an argument based upon international law would influence China's opinion on the subject.

If for whatever reason, China (which has nuclear weapons of its own, strong trade ties with the U.S., and lots of importance in world affairs especially in this region) strenuously objected, retaliating militarily would be much riskier for the U.S., Japan and/or their allies.

If China did not strenuously object, even if it raised token objections, retaliating militarily could probably proceed in a scenario in which North Korea was an international orphan with no allies, and the U.S. and/or Japan had myriad allies willing to offer any necessary assistance if requested.

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    Do you have a source for the airspace claim? It seems to me that the missile would be above the atmosphere for the majority of its flight.
    – phoog
    Aug 12, 2017 at 21:52
  • Many influential nations insist that the overflight by an orbiting satellite is legal. The dividing line between an ICBM test flight (with a dummy warhead) and a space launch system test flight (with a dummy payload) is a fine one, considering that both Sputnik and Explorer 1 were launched by rockets with a ballistic missile heritage. In fact, de-orbiting your debris after a test is a good thing.
  • The UN Security Council has called on North Korea to desist from missile tests, but the UNSC is not a world government, their legal right to ban North Korean "civilian" space use is questionable. North Korea is a member of the Outer Space Treaty.
  • Many nations have agreed to notify others in their region about launches, but I don't think that custom can be considered customary law.

So it would come down to "I know it when I see it" and that is a recipe for endless wrangling. If the five veto powers in the UNSC agree that the DPRK needs to be punished for their launches, that will happen. Otherwise, only if the North Koreans miscalculate and hit the island by accident.


If they exceed 100 km in height above Japan and land further than 23 km from Guam, it can be argued as legal. Additionally, they need to reasonably clean up after themselves and not just leave a spent missile in the sea.

To be polite, they should also announce the launch time and path in advance.

To be nice, they should cancel. There's too much risk of a mistake killing people, and the best-case outcome still contributes to global warming.

  • This answer needs to be more specific. How can it be argued as legal? Can you cite the specific laws, decisions, or legal concepts that are relevant? Has anyone done a legal analysis already? Aug 14, 2017 at 2:30
  • @indigochild: This is not law.sx Aug 14, 2017 at 23:18

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