Consent is not enough: why states must respect the intensity threshold in transnational conflict.

• Author: Hathaway, Oona A.

It is widely accepted that a state cannot treat a struggle with an organized non-state actor as an armed conflict until the violence crosses a minimum threshold of intensity. For instance, during the recent standoff at the Oregon wildlife refuge, the U.S. government could have lawfully used force pursuant to its domestic law enforcement and human rights obligations, but President Obama could not have ordered a drone strike on the protesters. The reason for this uncontroversial rule is simple--not every riot or civil disturbance should be treated like a war.

But what if President Obama had invited Canada to bomb the protestors--once the United States consented, would all bets be off? Can an intervening state use force that would be illegal for the host state to use itself? The silence on this issue is dangerous, in no small part because these once-rare conflicts are now commonplace. States are increasingly using force against organized non-state actors outside of the states' own territories--usually, though not always, with the consent of the host state. What constrains the scope of the host state's consent? And can the intervening state always presume that consent is valid?

This Article argues that a host state's authority to consent is limited and that intervening states cannot treat consent as a blank check. Accordingly, even in consent-based interventions, the logic and foundational norms of the international legal order require both consent-giving and consent-receiving states to independently evaluate what legal regime governs--this will often turn on whether the intensity threshold has been met. If a non-international armed conflict exists, the actions of the intervening state are governed by international humanitarian law; if not, its actions are governed instead by its own and the host state's human rights obligations.

Introduction I. The Intensity Threshold A. The Tadic Test B. The History of the Intensity Threshold 1. Common Article 3 2. Supporting State Practice, International Jurisprudence, and Scholarship C. The Intensity Threshold and the Prohibition on the Use of Force II. A Potential Loophole A. The Ad Bellum Inquiry B. The Presumption of Lawful Consent C. The Extraterritorial State's Limited Direct Human Rights Obligations D. The Potential Loophole III. The Stakes A. Use of Deadly Force 1. International Human Rights Law 2. International Humanitarian Law B. Detention 1. International Human Rights Law 2. International Humanitarian Law IV. Closing the Loophole A. How to Close the Loophole: Independent Obligations to Evaluate the Lawfulness of Consent 1. Limits on the Host State's Ability to Give Consent 2. Limits on the Intervening State's Ability to Accept Consent a. Requirement to Assess Consistency of Consent with International Law b. Complying with the Obligation in Practice B. Why Closing the Loophole Is "Good Law" 1. The Oregon Standoff: Highlighting the Importance of the Intensity Threshold in NIACs 2. The Canadians Strike: Highlighting the Importance of the Intensity Threshold in TNIACs 3. From Fiction to Reality C. Effectively Responding to Threats from Organized Non-State Actors Conclusion INTRODUCTION

On the afternoon of January 2, 2016, a group of activists occupied the headquarters of the Malheur National Wildlife Refuge, a facility managed by the U.S. Fish and Wildlife Service that had been left empty for the holiday weekend. (1) The armed activists, (2) led by brothers Ammon and Ryan Bundy, announced that "they had as many as too supporters with them." (3) Ammon Bundy indicated that the group "plann[ed] on staying [at the Refuge] for years," and its members would be willing to fight and die for its cause. (4) While the Oregon occupiers cited local concerns, they also questioned the authority of the federal government on myriad issues. (5) And they are not alone: there are over 200 armed militia groups in the United States, many of them with similar antigovernment views. (6)

Although the Oregon events may seem far removed from the concerns of international law, they help illustrate a potential loophole in international humanitarian law. An international armed conflict commences as soon as one state uses military force against another. But conflicts between states and organized non-state actors are different. Such conflicts must meet a minimum intensity threshold before they become non-international armed conflicts (NIACs), as opposed to riots or civil disturbances. And, until a NIAC is established, a state's actions are governed by its domestic laws and human rights obligations, rather than international humanitarian law. The threshold requirement may appear to be a mere technicality, but it is vitally important: without it, the rhetoric of the Oregon occupiers, the rise of associated militias, and the growing threat of domestic terror might have been enough for the U.S. government to conclude that it was in a NIAC with the organized militia group and employ military force in response.

The intensity threshold for establishing the existence of a NIAC is well-established and uncontroversial; clearly, not every riot or civil disturbance should be treated like a war. But what if the state in which the organized non-state actor is located invites another state to intervene? Are all bets off? Can the intervening state use force that would be illegal for the host state to use itself? Thus far, international lawyers have not adequately confronted this dilemma. (7) The silence is dangerous, as it leaves a potential loophole that states may use to avoid legal rules that constrain the use of violence by states against organized non-state actors.

The idea that President Obama might have invited Canada to use military force against the Oregon occupiers may seem ludicrous, but the legal dilemma the scenario poses is not simply academic. States are increasingly inviting or consenting to the use of force by outside states against organized non-state actors in their territories.

One of the most notable recent cases is in Syria: In September 2015, Russia began conducting air strikes against various non-state actor groups at the request of Syrian President Bashar al-Assad. (8) Kremlin Chief of Staff Sergey Ivanov emphasized that Russia had received consent for the intervention, stating that Assad had "turned to [Russia's] leadership, requesting military assistance." (9) Russia initially claimed to be targeting only the Islamic State (sometimes also referred to as ISIS), but later explained that it would target "all terrorists" in the country. (10) The United States and the European Union, along with representatives of the Syrian rebels, alleged that Russia's true targets were antigovernment opposition groups. (11) As of mid-2016, Russian strikes had reportedly killed over two thousand civilians. (12)

Or consider the Gulf Cooperation Council's (GCC) intervention in Bahrain. In mid-February 2011, protesters began occupying Pearl Square in the Bahraini capital of Manama. (13) On March 14, 2011, roughly 1500 troops--approximately 1000 from Saudi Arabia and another 500 from the United Arab Emirates (14)--entered Bahrain at the invitation of the Bahraini government. (15) Bahrain's King Hamad declared a state of emergency on May 15, and security forces forcibly cleared the square the following day. (16) At least six people died in the March 16 crackdown, (17) and at least thirty civilian deaths have occurred in total. (18) The Bahrain Independent Commission of Inquiry found that many of these deaths "resulted from the use of excessive and unnecessary lethal force." (19)

In the Mediterranean Sea, the European Union continues to conduct "Operation Sophia," a naval operation intended to combat people-smugglers off the Libyan coast. (20) In addition to interdiction efforts, the operation also includes training for the Libyan Coast Guards. (21) But, as of September 2016, all anti-smuggling operations and training must take place on the high seas because the Libyan government has not yet granted permission for EU forces to enter its territorial waters. (22) If the European Union eventually secures Libya's consent--which has been anticipated for months--it will be deploying military forces to conduct what are essentially police actions inside Libya's borders. (23)

The rise of interventions by consent is due in part to the fact that organized armed non-state actors are gaining power globally. In addition to al Qaeda, the Islamic State, and their affiliates across the globe, there are also drug cartels in Latin America, the Free Papua Movement in Indonesia, the Kurdistan Freedom Party in Iran, the FARC in Colombia, and countless others. (24) Many of these non-state groups are in armed conflicts with both their host states and extraterritorial states. In fact, conflicts between non-state actors and extraterritorial states have become so common that they now have their own label: "Transnational Non-International Armed Conflicts," or TNIACs for short.

Does the intensity threshold requirement for establishing a NLAC still apply to these conflicts? The answer, this Article concludes, is yes. Host state consent solves the jus ad helium concern for the intervening state, insofar as it makes permissible what would otherwise be an unlawful violation of the host state's sovereignty. But host state consent does not require that an armed conflict exists, a distinct analysis that will often turn on whether the intensity threshold has been reached.

We argue that the logic and foundational norms of the international legal order require the intervening state to independently evaluate whether a NLAC exists between the host state and the organized non-state actor. Host states violate international law by consenting to actions that their own human rights obligations or domestic laws would prevent them from taking themselves. The corollary principle holds that intervening states cannot rely on host state consent to...