President George W. Bush’s 2003 “mission accomplished” speech is one recent example of not knowing when a war is over. According to a new report by the Harvard Law School Program on International Law and Armed Conflict, or PILAC, the question of when a war has ended has only gotten more complex, and in many situations, international law does not necessarily provide enough guidance. The Bulletin spoke with Professor of Practice Naz K. Modirzadeh ’02, PILAC’s founding director and co-author of the report “Indefinite War: Unsettled International Law on the End of Armed Conflict,” about the implications of this failure of law.

What was the genesis of this report?

In 2014, when PILAC was founded, many were anticipating that President Obama would soon end the war in Afghanistan. And in talking with members of the armed forces in various allied countries as well as with scholars and NGO legal staff, we realized that there did not seem to be a shared understanding of when we would know that the conflict was over. Some people argued it would be when all detainees were released. Others argued it would be when the fighting was over, and others argued it would be when the enemy had been completely defeated. We were somewhat surprised by that, and we increasingly found, as we looked into the research, that while some scholars had identified and addressed this problem already, there was a real gap in applied research in international law on this question.

Has international law always struggled to define whether or not an armed conflict exists, or has the gap between the law and current types of warfare grown?

Part of the problem here is that within the law there are two types of armed conflict. One is called international armed conflict, and it is the very clear and quite thick set of rules that apply to wars between states. Then there is a kind of armed conflict that we call non-international armed conflict. In general, this was always thought of as a government fighting against rebels or insurgents within their own territory. And there were far fewer rules created within international law applicable to that kind of conflict. What’s new seems to be that the United States and a number of other governments are increasingly involved in non-international armed conflicts in other countries. For example, in Somalia, in Afghanistan, in Iraq, in Syria, the U.S. and many of its allies do not think of themselves as in an armed conflict against the state, but they are in an armed conflict against an armed group. What does it mean if the law does not answer the question of how these conflicts end?

Are there specific ways that international law governing conflict needs to shift to encompass new realities or definitions of conflict?

We are very careful to not take prescriptive policy positions. Our sense is that it’s valuable for institutions like HLS to engage in rigorous research in international law and its practical application, but to avoid advocating for particular approaches or particular outcomes. Our sense is that there is a lack of law here, and perhaps a lack of creative legal thinking on how to address this problem. Our view is that this area needs a lot more thought, a lot more analysis, and perhaps a greater appreciation of the high stakes of not having a legal answer to this question.

Who is responsible for figuring out the question?

How do we know when an armed conflict is over?

The most formal legal answer is that this is a problem that has to be solved by states. If states are the ones who create and interpret and apply international law, then they are the ones that have to recognize that this is a weakness and come up with a solution to it. More broadly, this is such a high-stakes issue that you really need to make sure that the conversation around how we solve this problem is an inclusive one, a global one, and takes into account the concerns of many states who may not be involved in the so-called war on terror but are very much affected by armed conflict, by non-international armed conflict specifically, and may benefit from deep thinking on the question of how law understands when wars end.

What are the stakes?

International law is far less tolerant of violent harm in situations other than armed conflicts. For example, use of lethal force is inherent to waging war, whereas in law enforcement governed by international human rights law in peacetime, the use of lethal force may only be used as a last resort. The most significant stakes in whether an armed conflict continues to exist or has ended concern the legal parameters pertaining to protecting civilians; starving, detaining, and killing an enemy; incidentally killing civilians who are not directly participating in hostilities; destroying an adversary’s property; damaging the natural environment; occupying foreign lands; and allowing access for humanitarians.

How would citizens and countries benefit if there were a clearer conception of international law on these issues?

One dilemma that international law faces is perhaps a deepening sense of skepticism about whether international law actually can achieve any of these laudable goals around ending conflict. As we look at a tragic situation like Syria, I think there are many who think, What would be the point of developing more international law if we have such a hard time enforcing the law that we already have? But the lives of people in places that are affected by war are tremendously affected by the question of whether or not we know when armed conflicts end, and when we know that the laws of armed conflict cease to apply. You also, I think, can argue that citizens have an enormous interest in hoping for an understanding that peace is achievable, and that wars do end, and that when they end, life should change.