Was the Downing of the Russian Jet by Turkey Illegal?

There has been much talk of improvement of the relationship between Russia and the West following the deadly terrorist attacks in Paris two weeks ago. Whatever gains have been made on that front will risk being reversed following Tuesday’s incident involving the Russian and Turkish air forces. Although the exact facts are—and likely will remain—disputed, the essence of the incident is known: a Russian fighter jet was shot down in the morning of 24 November by the Turkish military near the Turkish-Syrian border. This post weighs the international law considerations raised by the incident and suggests that on the basis of the available facts, the question from the title should likely be answered in affirmative.

The Russian SU-24 jet was in the region as part of the recent military offensive conducted by the Russian forces with the consent of the government of Syria against a number of armed groups on the Syrian territory, including the notorious Islamic State. The central contested fact is, of course, whether the aircraft had crossed over the border into the Turkish airspace. The Turkish prime minister Ahmet Davutoğlu emphatically claimed that it had; the Russian president Vladimir Putin denied it in equally strong words. An unnamed US official was reported as having said ‘that the Russian incursion into Turkish airspace lasted a matter of seconds’. Later, a Turkish letter addressed to the President of the Security Council (and duly leaked online) stated the incursion had lasted for exactly 17 seconds.

The legal analysis under international law is reasonably clear if the Russian version of the events is taken as factually accurate. The shooting down of another State’s military aircraft amounts to a use of force against that State. The recognized exceptions of the use of force in self-defence and under the authorization of the Security Council being inapplicable on the facts, the destruction of the jet would be caught by the general prohibition on the use of force under Article 2(4) of the UN Charter and thus unlawful.

What if, however, Turkey was right and the Russian jet had indeed crossed the border into the Turkish airspace? There is little doubt that, as the ICJ held in the Nicaragua case, the ‘unauthorized overflight of a state’s territory by aircraft belonging to or under the control of the government of another state’ directly infringes the territorial sovereignty of the overflown State (at para 251). This general observation should be tempered by noting that if such an incursion had been caused by bad weather conditions or navigational error, its wrongfulness could have been precluded on the grounds of distress or force majeure (see ILC Draft Articles on State Responsibility, commentary to Article 23, para 5, fn 351). Nevertheless, no such claims appear to have been made thus far. Therefore, even accepting that the unauthorized overflight amounted to a breach of international law, does it follow that Turkey as the overflown State was entitled to respond by destroying the infringing aircraft?

As an aside, for civil airplanes, the answer is almost always negative. The applicable lex lata is to be found in Article 3 bis of the Chicago Convention on International Civil Aviation, adopted in response to the shooting down of the Korean Air Lines Flight 007 over the territory of the Soviet Union in 1983. The provision stipulates that States must refrain from using weapons against civil aircraft in flight and it prohibits the endangering of the lives of passengers in case of interception. This means that shooting down a civilian aircraft, even if directly following an unauthorised incursion into the acting State’s airspace, would constitute a violation of the applicable law (for a more detailed analysis, see this excellent post by Kimberley Trapp from 2011).

However, the Russian jet was decidedly not a civilian aircraft. As such, the response to its (supposedly) unauthorized overflight falls to be determined by the application of the general rules of international law. One could question whether the act of shooting down a foreign plane over one’s own territory amounts to a use of force in the sense of Article 2(4) of the UN Charter. It is open to doubt whether such an act can be accurately described as being ‘against the territorial integrity or political independence’ of the intruding State or as ‘inconsistent with the Purposes of the United Nations’. The practice of States in this area is mixed: in his book Law Against War, Oliver Corten details several instances of aerial incursions when the defensive action was treated as ‘a simple police measure’ and Article 2(4) was not invoked by either of the involved States (at pp. 63-65).

Whether responding to aerial incursions is governed by the regulations on the use of force or (as Corten argues) by the lex specialis rules on policing one’s airspace, it is clear that international law does apply to such incidents. Although the two potentially applicable regimes admittedly differ in their nuances, under both of them, any defensive action against the intruding aircraft must meet the twin requirements of necessity and proportionality.

It is generally accepted that the overflown State may respond by force when the overflight is conducted for apparently hostile reasons. For example, when the Soviet Union shot down an American U2 airplane flying over the Soviet territory on a reconnaissance mission in 1960 in the context of the Cold War, the US did not issue a protest against the attack nor against the ultimate imprisonment of the pilot. It can be inferred from incidents such as that one that shooting down a military airplane on a hostile mission over the targeted State’s territory may be justified under international law (and some of the period literature did indeed infer as much: see at p. 287).

However, the same would not apply where no such hostile intent is readily apparent or capable of being reasonably inferred from the context of the incursion. As Tom Ruys puts it, ‘intruding aircraft whose intentions are known to be harmless must not be attacked even if they disobey orders to land’ (at p. 191). The exact intentions of the Russian pilots may still be subject to speculation, but the context of their supposed overflight—in other words, the ongoing Russian military operations in Syria—indicates that any incursion would not have posed a direct threat to Turkey. Another potential indicator of a hostile intent is the accumulated or repeated nature of the incursions. This is one of the factual questions that still needs to be determined, but according to press reports, Turkey did complain in the past that Russian planes engaged in the Syrian conflict had been repeatedly straying across the border.

In any event, the brevity of the incident (likely measured in seconds only) coupled with the limited evidence of any direct threat vis-à-vis the territorial State suggest that the injury suffered by Turkey was relatively minor. The incursion would have amounted to a violation of the territorial sovereignty of the overflown State as per the Nicaragua case (see above) but in the absence of any coercive element, it would not have violated the principle of non-intervention (see ibid, at para 205).

It thus appears that the destruction of the intruding Russian jet would have exceeded the bounds of proportionality as less severe means had been available to Turkey. In particular, these would have included the issuance of warning (which Turkey claims it had done, but Russia disputes) and the interception of the intruding aircraft with the aim of expeditiously removing it from the airspace of the territorial State. As the Russian jet seems to have been shot down following a very brief incursion into Turkish airspace and as there were other less severe means available, its downing appears to have breached international law.

Undoubtedly, more facts will emerge in the coming days, some of which may affect the conclusion reached above. For now, we should hope together with Donald Tusk, the president of the European Council, that all involved will ‘remain cool headed and calm’ and that Tuesday’s events will not lead to further escalation in the region and worldwide. However the events shall unfold, the conservative interpretation of international law advanced in this post should be seen as one of the important ways in which international law serves to prevent unnecessary confrontations of this kind in the future.