Twice in recent months military and political leaders from Israel have reportedly cancelled trips to Britain out of concern that they might be arrested for alleged war crimes.
Officials from other countries could soon face a similar greeting – not only in Britain but also in France, Germany, Japan and other nations that are members of the International Criminal Court.
In May, the international court’s member states will meet in Kampala, Uganda, to consider adding a new crime of aggression to the offenses the court can prosecute. If they include it, all member nations will be required to arrest officials accused of that crime – even if they come from countries that refuse to join.
The Rome conference that created the international court in 1998 gave it power to prosecute four international crimes. One was aggression. Unable to reach consensus on what the term meant, the conference left it undefined. As a result, the crime of aggression has not been prosecutable.
But that would change if the newly-proposed definition were adopted. Under it, any political or military leader would be guilty of the crime of aggression if he exercises control or direction over any use of armed force that represents a manifest violation of the United Nations Charter.
Sensible enough in concept, the definition is maddeningly vague in application, largely because it is based upon a 1974 General Assembly resolution that was aimed at guiding state conduct, not defining individual criminal liability.
What constitutes a "manifest" violation of the charter? The truth is it’s impossible to say. The charter prohibits any non-defensive use of force not authorized by the Security Council. Yet five years ago a U.N. high-level panel found that violations of the charter’s use-of-force rules have been too numerous to count. By one count, the panel noted, force had been used 200 times from 1945 to 1989; by another count, 680 times. In almost all those conflicts, every nation involved contended that it acted lawfully. No impartial tribunal existed to decide which side was right.
Which individuals within those "aggressor" states exercised control or direction over the military actions in question? Again, one can only guess. Preparation for armed conflict engages numerous high-level diplomats, lawyers, intelligence analysts and, sometimes, legislators.
Precisely who exercises control or direction is therefore unclear. What is clear is that, had the proposed crime existed over recent decades, every U.S. president since John F. Kennedy and hundreds of political and military leaders from other countries would have been subject to potential indictment, arrest and prosecution.
Concern about potentially politicized prosecution is one reason that China, Russia, India and the United States have not become members of the international court.
Yet it would not matter for officials from those states that their countries have declined to join. Military action by their states could still be characterized as "aggression" under the proposed definition. If that action were to occur within the territory of a member state – there are now 110 – an indictment could issue. Other member states would thereafter be required to arrest the accused, who would then be transferred to The Hague to stand trial.
Max Weber wrote of the imperative of "calculability" in a legal system, the need to ensure that risks can be identified and addressed with reasonable predictability. In the contemporary international legal order, the "principle of legality" assumes this function. The principle requires that a criminal defendant be given clear notice as to what conduct is illegal before it occurs. Its aim is to provide a modicum of systemic stability by discouraging arbitrary arrest and prosecution.
The proposed new crime will undermine that principle, which lies at the heart of the rule of law. It will force hundreds of political and military leaders who act in good faith to guess when and where they will be arrested in their international travels. It will strain relations among allies and exacerbate tensions among adversaries. It will bollix an international equilibrium that already is precarious enough.
The 1998 treaty that established the International Criminal Court provides that it will be applied "consistent with internationally recognized human rights." If the parties to the treaty honor that commitment in Kampala, they will reject this misbegotten new definition of aggression.
Michael J. Glennon is professor of international law at the Fletcher School of Law and Diplomacy, Tufts University, and the author of the forthcoming book "The Fog of Law: Pragmatism, Security and International Law."