Following a new outbreak of violence in eastern Ukraine on Thursday, tensions in Ukraine and between Russia and the United States and NATO countries are high ahead of Ukraine’s presidential elections Sunday. Russian troops remain along Ukraine’s eastern border, notwithstanding Moscow’s promise of withdrawal.
In this murky situation, however, it is crucial to rely on several foundational principles of international law to protect persons, sovereignty, and national security. The conflict in Ukraine demonstrates the importance of sustaining the strict separation between the law of armed conflict (LOAC) and the jus ad bellum, a low threshold for recognition of international armed conflict, and the principle of distinction in today’s conflicts.
The following series by Laurie R. Blank will explore each of these points in detail.
Part I: Jus ad Bellum and LOAC: Maintaining the Separation
Laurie R. Blank
Ukraine’s ongoing crisis has presented complicated geopolitical and diplomatic issues and will continue to do so. From the perspective of the international law that applies to the use of force and the law of armed conflict, however, the situation offers a useful opportunity to reinforce several foundational international law principles and precepts that are integral to the protection of persons, sovereignty and national security. Events in Ukraine highlight three specific central concepts: the strict separation between the law of armed conflict (LOAC) and the jus ad bellum; the low threshold for recognition of international armed conflict; and the overarching importance of the principle of distinction for the fulfillment of LOAC’s central goals in today’s conflicts.
Legal questions arise within two distinct paradigms: jus ad bellum, the law governing when states can use force, and LOAC, which governs the conduct of states and individuals, and the protection of persons, during armed conflict.Much of the debate during the early weeks of the crisis centered on the lawfulness of Russia incursion in Crimea and use of force against Ukraine’s territorial sovereignty. As Russian forces massed along the Ukrainian border and Ukrainian forces fortified positions along the eastern border (before the recent bouts of violence in eastern Ukraine), the authority to use force has remained a primary issue.
The jus ad bellum, set forth primarily in the United Nations Charter, is the foundation of the U.N.’s goal of “sav[ing] succeeding generations from the scourge of war.” Article 2(4) prohibits the use of force against another state: “All members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state . . . .” There are three exceptions: the consent of the territorial state, U.N. Security Council authorization under Chapter VII, and self-defense under Article 51.
Jus ad bellum determines when a state’s use of force across borders is lawful. LOAC only applies during armed conflict and sets the parameters for lawful conduct during conflict. Both bodies of law apply to the use of force, but in separate and different ways. Jus ad bellum is not concerned with the conduct of hostilities, the targeting of persons or objects or the extent of civilian casualties. But these issues are foundational to LOAC, and essential to the protection of combatants and civilians alike.
Ukraine’s crisis reminds us of the historic and essential separation between these two bodies of law. If the situation devolves into violence between the two states, would they have different rights based on the lawfulness of use of force? If Russia were determined to be using force unlawfully in Ukraine, would its obligations under LOAC be affected in any way? Would its soldiers lose their rights and privileges under LOAC? Alternatively, would Ukraine, if acting in self-defense to repel a Russian incursion, have greater latitude in its conduct?
The answer is a resounding “no.” The legality of action under jus ad bellum does not change the application of LOAC — or vice versa. Indeed, LOAC relies on the equal application of the law to all parties to conflict, a principle that dates as far back as Grotius, Suárez and Gentili.
This strict separation reinforces that all parties have the same obligations and rights during armed conflict, ensuring that all persons and property benefit from LOAC’s protections. Both Common Article 2 to the Geneva Conventions and the preamble to Additional Protocol I codify the distinction between the lawfulness of going to war and the lawfulness of conduct during war. As the preamble to AP I states, the Geneva Conventions and Additional Protocol I “must be fully applied in all circumstances . . . without any adverse distinction based on the nature or origin of the armed conflict or on the causes espoused by or attributed to the Parties to the conflict.”
Since Nuremberg, tribunals have firmly rejected any efforts to conflate jus ad bellum and LOAC. At Nuremberg, where both jus ad bellum and LOAC crimes were prosecuted, the Tribunal consistently rejected the Prosecution’s argument that Germany, as the aggressor, was not entitled to LOAC rights and protections. For example, in the Justice Trial, the Tribunal declared:
If we should adopt the view that by reason of the fact that the war was a criminal war of aggression every act which would have been legal in a defensive war was illegal in this one, we would be forced to the conclusion that every soldier who marched under orders into occupied territory or who fought in the homeland was a criminal and a murderer.
More recently, the Special Court for Sierra Leone reaffirmed this approach. The Trial Chamber reduced the sentences of two leaders of the Civil Defence Forces, a militia fighting with the government, because they fought for “a cause that is palpably just and defendable” — notwithstanding their brutal crimes. This decision — explicitly accepting that those fighting in a just war bear lesser responsibility under LOAC — would have sent a highly problematic message that LOAC does not apply equally to all parties.
On appeal, however, the Appeals Chamber flatly rejected this violation of the “bedrock principle” of international law separating jus ad bellum and LOAC. The court emphasized that “[a]llowing mitigation for a convicted person’s political motives, even where they are considered . . . meritorious . . . provides implicit legitimacy to conduct that unequivocally violates the law.
The effectiveness of both jus ad bellum and LOAC depend on this separation. If conduct during war could impact the lawfulness of using force, the jus ad bellum framework would be emasculated. And if the cause at arms influenced a state’s obligation to abide by the laws regulating warfare and requiring protection of civilians, states would justify all departures from LOAC by trumpeting the purported justness of their cause. The result: an invitation to unrestricted warfare. Imagine if a state fighting in self-defense could argue for a “no-holds barred” approach in order to stave off an aggressor. Or if an aggressor state, facing recriminations for violating the jus ad bellum, simply gave up on LOAC compliance because it was already on the wrong side of international law. Individuals, residential areas, cultural and religious sites, hospitals, detainees — all would lose the LOAC protections that very often are the difference between life and death.
The rules of LOAC thus apply with equal force to a state waging aggressive war or a state fighting in self-defense. And jus ad bellum applies with equal weight to a state fighting in accordance with LOAC or a state fighting in violation of LOAC’s core tenets. Neither the politics of the crisis nor the lawfulness of either state’s actions can dilute the essential obligations, rights and protections each party bears and enjoys under international law.
Laurie R. Blank is a Clinical Professor of Law and Director, International Humanitarian Law Clinic at Emory University School of Law.