As Far As We Know, There Has Been No Armed Attack Against Poland

Yesterday a missile struck a village in Poland, near the Ukrainian border, prompting immediate fears of escalation and of a more direct entry of NATO states into the Russian/Ukranian armed conflict. As I write this it remains unclear whether the missile was fired by Russian or by Ukranian armed forces. However, US President Biden and other US officials have expressed doubts that Russia fired the missile, while Russia itself has denied attacking Polish territory and asserted that the missile came from a Ukrainian S-300 air defence system.

Again, as things stand the facts are yet to be conclusively established. But from what we know at the moment it seems unlikely that Russia deliberately targeted Polish territory, including because it had nothing to gain and much to lose from such an action. Two hypotheses seem more likely: (1) that the missile was indeed fired by Russia, despite Russia’s protests to the contrary, but at a target in Ukraine and that it somehow got misdirected, through operator error or mechanical failure; (2) that the missile, in fact, came from a Ukranian S-300 system that was fired in response to Russia’s ongoing missile strikes against Ukraine, but that again somehow got misdirected and hit Polish territory.

If either of these hypotheses is true, force was used against Poland, by Russia or Ukraine respectively, in a manner contrary to Article 2(4) of the UN Charter, and in violation of Polish territorial sovereignty. But the force did not rise to the level of an ‘armed attack’ within the meaning of Article 51 of the Charter, because Poland was not targeted intentionally. Rather, the force used against Poland was a ‘frontier incident’ within the meaning given to that term by the International Court of Justice in cases such as Nicaragua and Oil Platforms. Accordingly, the right of individual or collective self-defence under Article 51 does not arise, and Article V of the North Atlantic Treaty is therefore not applicable either. 

There is little doubt that the notion of an armed attack in Article 51 includes not just considerations of gravity and scale of the force used, but also those of intentionality. (For probably the most comprehensive treatment of the subject I would direct readers to Tom Ruys, ‘Armed Attack’ and Article 51 of the Charter, at 158-168.) States have generally not treated accidental uses of force as armed attacks giving rise to self-defence – when its embassy in Belgrade was destroyed by NATO in 1999, for example, which NATO explained as an accident, China did not assert that it was a victim of an armed attack. To be clear here, the intention required by the notion of an armed attack excludes considerations of purpose or motive, but is simply one that the organs of state A have directed a hostile action against state B. On the hypotheses above, neither Russia nor Ukraine had such intent to attack Poland. And even if the notion of armed attack was construed as a purely objective one, contrary to what I have said above without incorporating any element of intentionality, in the case of an accidental spill-over scenario such as this one there would be no necessity for Poland and its allies to respond in self-defence by using force.

That Poland was likely not the victim of an armed attack does not mean that it has not been wronged. Prohibited force, in the sense of Article 2(4) of the Charter, and the duty to respect sovereignty, do not require a similar element of intentionality. Depending on who fired the missile, either Russia or Ukraine would have the duty to provide adequate reparation to Poland, including measures of satisfaction and compensation, especially because two lives were lost.

That said, a particular issue arises with respect to Ukraine (but not Russia): on the hypothesis that Ukraine was responding to a Russian attack and launched S-300 missiles in the exercise of its own right to self-defence, which in error spilled over onto Polish territory, would Ukraine be able to rely on self-defence against Russia as a circumstance precluding wrongfulness vis-a-vis Poland, thus obviating any duty to provide reparation? This would essentially be a ‘mistake of fact’ scenario in Ukraine’s own use of force in self-defence, which I have extensively previously examined on the blog here, here and here. To put a long story short, on one view Ukraine would be responsible for any errors its organs and agents have made, however innocent, and Poland in particular could not be expected to bear the cost of a use of force against it. On another view, an honest and reasonable mistake of fact could operate as an excuse or justification – if the relevant Ukrainian agents did all that could reasonably be expected of them to prevent the S-300 system from hitting Polish territory while defending Ukraine against Russian attacks, Ukraine’s own reliance on self-defence would preclude the wrongfulness of the injury done to Poland. (My own view is that the former option is at least generally the right one in the ad bellum context; this is of course also an issue that arises in other contexts, especially in responses to cyber attacks). It will be very interesting to observe what legal positions the affected states eventually take on this matter, in the case the hypothesis of a misdirected Ukranian S-300 strike ultimately proves correct.