In the days following the shooting down of MH17, the UN and governments around the world have quickly turned to discussing how to bring the perpetrators to justice. While the most likely scenario is that pro-Russian Ukranian rebels shot down the aircraft by mistake, the lack of clarity around the circumstances of the attack continues to complicate any attempts at resolution. Pending a full investigation and more evidence about responsibility, it is difficult to talk of accountability under international law.

Nevertheless, it seems clear that the MH17 incident represents a crime under international law. It's likely that the conflict between the state and rebel forces in Ukraine can be characterised as an armed conflict under international law, and that therefore international laws of war relating to internal conflict apply.

The principle of distinction between civilians and combatants is one of the main tenets of international humanitarian law. In armed conflicts of this nature, making civilians the object of attack is directly prohibited under treaty law, and the prohibition against targeting civilian objects has been found to be a customary international legal norm by the International Committee of the Red Cross (ICRC). 

In accordance with state practice and international jurisprudence, the ICRC has confirmed the existence of a customary international norm requiring all feasible precautions to be taken to avoid injury to civilians and damage to civilian objects. Similarly, parties to a conflict must do everything feasible to verify that targets are military objectives.

It is clear that the perpetrators of the MH17 disaster have violated both treaty law and customary international law in attacking civilians and a civilian object, and failed to take all feasible precautions to ensure the military nature of the target. Holding them accountable for these actions will be another story.

In public debate around the incident, a number of options for legal recourse have been raised.

The first is to prosecute the perpetrators of this crime under the domestic law and courts of one of the injured parties. This was the approach taken for the Lockerbie bombing trial, in which two Libyan nationals were tried under Scottish law in the Netherlands for their involvement in the bombing of Pan Am Flight 103 over Scotland. Ukraine would certainly have jurisdiction over any crime committed in its airspace, and it is likely that injured nations such as the Netherlands, Malaysia, or even Australia may also have jurisdiction to prosecute this crime.

Another is that the perpetrators of the incident be brought before the International Criminal Court (ICC). The ICC is charged with dealing with individuals for the offences of genocide, crimes against humanity, war crimes, and the crime of aggression. As prosecution of crimes against humanity requires acts to be committed as part of a 'widespread and systematic attack,' the most likely avenue for pursuing justice for victims of the MH17 attack in the ICC would be under the Court's jurisdiction over war crimes.

However, assuming that Ukrainian rebels linked to the Donetsk People's Republic were responsible for shooting down MH17, the prospects for having these individuals appear in front of the ICC are limited. To complicate matters further, a number of key figures in the Donetsk People's Republic are known to hold Russian citizenship, and it is alleged that some, including the Donetsk 'prime minister', have connections with Russian intelligence agencies. While both Ukraine and Russia are signatories to the Rome Statute of the ICC, neither has ratified the treaty yet, meaning that although they are required to refrain from  acts which would defeat the object and purpose of the treaty, compelling them to submit their nationals to the jurisdiction of the court would be more complicated.

This then raises the issue of state responsibility. If it is found (and this is a very big 'if') that the attack on MH17 was perpetrated by a Russian national acting in (or even beyond) their capacity as an official of the state, this could give rise to Russian state responsibility under international law. Russia could similarly be implicated if the rebels were found to be acting under Moscow's instructions, direction or control. 

Even if it is found that Russia had no involvement in this specific incident, as may well be the case, there is still the question of Russia's broader involvement in the conflict in Ukraine. Here, the International Court of Justice's (ICJ) ruling on Military and Paramilitary Activities in and against Nicaragua may provide some guidance. In 1986, the ICJ presided over a case brought by Nicaragua against the US over America's support for the contras rebel group against the ruling Marxist-Leninist Sandinistas. By financing, organising, training, supplying and equipping the contras, the US was found to be in violation of the customary international legal norm of non-interference in the internal affairs of states and the prohibition against the use of force. However, the court found that due to a lack of 'effective control' over the rebel contras, the US could not be held accountable for specific breaches of international humanitarian law committed by the group.

Unless Russia is found to have exercised effective control over the Ukrainian rebels, questions would linger over how far Russia could be held accountable. However, depending on the details of Russia's involvement, there may be an international legal case to be made in a forum such as the ICJ about Russia's broader support for Ukranian rebels.

Yet even if Russia was to be implicated, states are not required to submit to the jurisdiction of the ICJ, and neither Russia nor Ukraine have accepted the permanent jurisdiction of the Court . The likelihood that Russia would accept ICJ jurisdiction in the event of a dispute is almost zero. Similarly, by virtue of its permanent membership, it is safe to expect that any UN Security Council resolution directly implicating Russia in any of these scenarios would be swiftly vetoed. And all this is further complicated by the fact that the extradition of Russian nationals, even those who have committed a crime in the territory of a foreign state, is prohibited by Russia's constitution and criminal code. 

None of this undermines the need for a complete investigation of the circumstances leading up to the incident. Australian diplomacy has already proven invaluable in securing a robust UN Security Council resolution recognising the need for a full, thorough and independent investigation. At this point, continued diplomatic, economic and political pressure in enforcing Resolution 2166 may be the best states can do to ensure justice for the victims of MH17.