ISIS has changed international law

The United States government initially invoked several different legal arguments in arenas such as the UN and U.S. Congress to justify airstrikes against ISIS in Syria.

These included the right of humanitarian intervention (controversial without a UN Security Council resolution), the right to use force in a failed state (equally controversial) and the right of “hot pursuit” (usually used to justify pursuing ships in international waters). None of these had a solid grounding in international law that would have justified violation of another country’s sovereign territory.

Finally, the U.S. officials settled on a novel argument under the rubric of self-defense.

Even in the aftermath of the al-Qaida attacks in the United States on 9/11, the use of force in self-defense against terrorists within another sovereign nation had not been viewed as lawful unless the terrorist organization was under the effective control of that nation. This is a position that had been repeatedly reaffirmed by the International Court of Justice.

But the United States argued that such force can be legally justified where a governing authority is unable or unwilling to suppress the threat operating within its borders.

The shift
That view was not initially accepted by Russia, China, or even the United Kingdom.

However, their position changed in the aftermath of the ISIS attacks on the Russian jetliner and on the Paris stadium and theater. This, in turn, led to the unanimous adoption of a UN Security Council resolution calling on nations to use “all necessary measures” to fight ISIS in Syria.

UN Security Council Resolution 2249, adopted in November 2015, does not clearly endorse a particular legal justification.

But despite its ambiguity, it will likely be viewed as confirming that use of force in self-defense is now permissible against “nonstate actors” such as terrorists when the territorial state is unable to suppress the threat that they pose.

In the aftermath of the adoption of the UN Resolution, Russia and the United Kingdom joined the United States in bombing ISIS targets in Syria.

Today, sixty-six nations, according to Secretary of State John Kerry, are united to fight ISIS.

Implications for the future
The implication of this newly accepted change in the international law of self-defense is that any nation can now lawfully use force against deadly nonstate actors in another country if the government of that country is unable or unwilling to suppress the threat within its borders.

However, use of force under this new approach is still subject to limits imposed by what is known as customary international law, or the practices that the international community of states customarily follow from a sense of legal obligation. More specifically:

• Only an armed attack can trigger the right to use force in self-defense. Mass terrorist attacks that result in hundreds of deaths meet that threshold. Smaller-scale incidents would not.
• The use of force must be targeted against a terrorist organization and not against the nation where the terrorist group exists, or that nation’s military, unless the nation is shown to be effectively in control of the offending group.
• Military action must still meet the international law principles of necessity, proportionality and discrimination.

While this new authority will certainly prove useful against ISIS, there is a likelihood that it will ultimately be used against a much broader group of threats. Such threats could include a variety of terrorist groups, as well as rebels, pirates or drug cartels.

The number of candidates for such self-defense action is quite large. The U.S. Department of State, for example, maintains a list of terrorist organizations that pose a significant threat to the United States and its allies around the world. This list includes fifty-eight terrorist groups headquartered in thirty-five different countries (in addition to ISIS in Syria/Iraq).

With so many potential targets in so many countries, one must ask whether the possibility of abuse will ultimately outweigh the benefits of weakening ISIS.

Michael Scharf is Dean and Director of the Frederick K. Cox International Law Center, Joseph C. Hostetler - Baker Hostetler Professor of Law, Case Western Reserve University. This article is published courtesy of The Conversation (under Creative Commons-Attribution/No derivative).