Show sidebar

Are the U.S. and U.K. parties to the Saudi-led armed conflict against the Houthis in Yemen?

series of posts at Just Security have focused on the rules that apply to U.S. and U.K. support for the Saudi-led coalition’s military operations against the Houthi rebels in Yemen. A key question is whether supporting States, like the United States and the United Kingdom, avoid becoming a “party” to the armed conflict (and thus being bound by international humanitarian law) by providing assistance that stops short of engaging in direct combat. What type of support will render an assisting State a party to this conflict?

I. Current scope of U.S. and U.K. support

U.S. assistance to the Saudi-led coalition has included providing weapons, sharing intelligence, targeting assistance, and aerial jet refueling. In March last year the spokesperson for the NSC declared that in support of the Gulf Cooperation Council’s actions against Houthi violence, “President Obama has authorized the provision of logistical and intelligence support to GCC-led military operations.  While U.S. forces are not taking direct military action in Yemen in support of this effort, we are establishing a Joint Planning Cell with Saudi Arabia to coordinate U.S. military and intelligence support.”

In the UK, a joint report released last week by the House of Commons Business, Innovation and Skills and International Development Committees and another report by the Foreign Affairs Committee both state: “The UK’s support for Saudi Arabia’s military intervention in Yemen has been extensive while remaining short of engaging in the actual combat. … Our involvement extends from providing the planes and bombs for airstrikes to UK personnel in the Joint Combined Planning Cell and Saudi Air Operations Centre.”

This type of support is not exclusive to the armed conflict in Yemen. For example, we witnessed similar assistance when the U.S. provided aerial refueling and ferried allied soldiers from African nations to support France in the armed conflict in Mali in 2013.

II. Approaches for determining whether a State is a party to a pre-existing non-international armed conflict (NIAC)

In a context such as this particular conflict in Yemen, in which the U.S. and U.K. are not directly engaged in fighting, the traditional 2-pronged test to find them party to a non-international armed conflict (a certain intensity of fighting and level of non-state armed group organization) won’t be met as there are no direct hostilities between them and the Houthis. Nevertheless, as I set out in earlier posts at Just Security in 2015 (see here, and here), two approaches can assist in determining, from the facts, whether a country has become a party to a pre-existing NIAC for the purposes of applying international humanitarian law (IHL): (1) the “support-based approach”; and (2) the concept of “co-belligerency” under the international law of neutrality.

The “support-based approach” is particularly relevant because “modern armed conflicts are increasingly being fought through coalitions and alliances of several states and/or international organisations whose involvement in the hostilities may vary…” Under this approach, a State will be considered a party to a pre-existing NIAC when the following four conditions are met:

  1. There is a pre-existing NIAC ongoing in the territory where the supporting forces intervene;
  2. The intervening forces undertake actions related to the conduct of hostilities in the context of the pre-existing conflict;
  3. The intervening forces’ military operations are carried out in support of a party to that pre-existing conflict;
  4. The intervening action in question is undertaken pursuant to an official decision by the country in question to support a party involved in the pre-existing conflict.

Ferraro explains that indirect forms of support such as the provision of weapons or financial support would not meet the test. Instead, there must be a “close link” between the action of the supporting forces and the harm caused to the enemy by specific military operations. For instance, “transporting the supported state’s armed forces to the front line or providing planes for refuelling jet fighters involved in aerial operations carried out by the supported state” would make the intervening State a party to the armed conflict. With respect to the third criterion of support, Ferraro adds that it must be evident that “two or more states or international organisations are pooling or marshalling military resources in order to fight a common enemy. … Setting up ad hoc joint military mechanisms or signing an agreement designed to enhance cooperation between the … forces and the armed forces of the territorial state in respect of the pre-existing conflict would certainly tend to suggest some form of support and therefore the existence of the required nexus.” The fourth criterion is simply meant to ensure that the support is intentional rather than resulting from a mistake or an act that falls outside the intervening forces’ authority.

The concept of co-belligerency under the international law of neutrality (designed to apply in international armed conflict) might also serve as a source of guidance to determine whether a supporting State is party to a pre-existing NIAC. Under the law of neutrality, a State will become a co-belligerent when, in association, cooperation, assistance or common cause with another belligerent it participates in hostilities to a significant extent or it systematically or substantially violates its neutrality duties of impartiality and non-participation in the conflict. Examples of violations of a State’s neutrality include supplying war materials, engaging its own military forces, supplying military advisors to a party to the armed conflict, or providing or transmitting military intelligence on behalf of a belligerent. Interestingly, the United States has borrowed the concept of co-belligerency to determine whether armed groups constitute associated forces of Al Qaeda for the purpose of applying the 2001 congressional authorization to use force. Geoffrey Corn has explained to the Senate Committee on Armed Services that “The focus on shared ideology, tactics, and indicia of connection between high-level group leaders therefore seems to emphasize both logical and legitimate intelligence indicators of which offshoots of al Qaeda fall into the category of co-belligerent.”

III. An obligation to ensure respect for IHL

While becoming a party to the conflict is what triggers the application of IHL, it is important to recall that even non-parties to armed conflict have general obligations when it comes to their support activities. Under common article 1 of the Geneva Conventions of 1949 and their Additional Protocol I, States must ensure respect for IHL by other parties to an armed conflict. Under the customary rule, they “may not encourage violations of international humanitarian law by parties to an armed conflict. They must exert their influence, to the degree possible, to stop violations of international humanitarian law.” This has been described as an obligation of due diligence under which “a State with close political, economic and/or military ties (for example, through equipping and training of armed forces or joint planning of operations) to one of the belligerents has a stronger obligation to ensure respect for IHL by its ally. …” This obligation is particularly relevant in the Yemeni context today in light of the influence that contributing countries like the U.S. (which has contested the obligation as a matter of law but seeks to promote adherence as a matter of policy) and the U.K. can have over Saudi Arabia in particular.

In fact, the IHL-related provisions of the Arms Trade Treaty (ATT) can be considered a derivative of this common article 1 obligation. In its section on Principles the ATT reiterates all States’ obligation to ensure respect for IHL, and in the body of the instrument translates this into two obligations: It prohibits arms transfers if the transferring State has knowledge that the arms would be used in the commission of certain war crimes; short of such knowledge, a State must carry out a risk assessment and refrain from exporting weapons if it finds an overriding risk that the arms could be used to commit or facilitate a serious violation of IHL. (A similar and possibly even stricter obligation exists in the EU Common Position on arms export controls.) The ICRC has just published an updated practical guide for making such risk assessments in arms transfer decisions. On the point at which the risk of violations requires a denial of transfer, it states that “any discernible pattern of violations, or any failure by the recipient to take appropriate steps to put an end to violations and to prevent their recurrence, should cause serious concern.”

* * *

There is certainly no shortage of reporting on the civilian casualties and general suffering in Yemen due to the conflict between the Saudi-led coalition and the Houthis. If the U.S., U.K., and possibly others are contributing to the conflict such that they are parties to it even without engaging in direct combat, then they are equally bound by IHL. For these parties, the IHL rule requiring that all feasible precautions be taken to avoid and minimize incidental loss of civilian life, injury to civilians and damage to civilian objects is especially relevant. In addition, whether or not the U.S., U.K., or other supporting countries are considered parties to the armed conflict alongside the coalition, their influence is certainly clear, as is their corollary duty to ensure respect for IHL.

* The views expressed herein are those of the author and do not necessarily reflect the views of the United Nations.

Tags: , , ,


About the Author

is Senior Legal Officer with the United Nations Office for the Coordination of Humanitarian Affairs.