The Saudi-led coalition in Yemen continues to eye a takeover of the Port of Hodeida, which has been under the control of the Houthi rebels since they forced President Abd Rabbuh Mansour Hadi to flee Yemen back in 2014. Experts have warned about the risk of war crimes should the Saudi- and Emirates-led coalition seize the port (see Monday’s article by Ryan Goodman and Alex Moorehead). Such an outcome is far from hypothetical given the multiple and ongoing allegations of war crimes by the coalition during its Yemen operation. But the widespread employment of foreign nationals in the military forces of the United Arab Emirates, a key partner in the Saudi-led coalition, presents a previously unnoticed avenue to deter atrocities and enforce international criminal law.

Commentators on Just Security have presented various legal analyses regarding the commission of war crimes by the Saudi-led coalition. Even with legal liability identified, however, it has been hard to make the case for deterrence when the likelihood of actual enforcement seemed so remote. The U.S. and U.K, both key supporters of the coalition, have largely rebuffed requests to investigate the allegations (although Scotland Yard at least has recently begun a “scoping exercise” on whether an investigation could be justified). Short of a UN Security Council referral (a non-starter given the veto power of those supporting the Saudi-led coalition), the International Criminal Court (ICC) does not have jurisdiction in Yemen because that country has not ratified the ICC treaty. The Court does have jurisdiction over nationals from one of the members of the Saudi-led coalition, namely Jordanians, since Jordan has ratified the ICC treaty. This means the ICC prosecutor, under her independent power to bring a case, could consider investigating a Jordanian national accused of war crimes. But the Jordanians play a minor role compared to other coalition member states, and none of the others have joined the ICC.

There is, however, a more promising (albeit surprising) opening for an ICC investigation: The Commander of the Emirati Presidential Guard, Major General Mike Hindmarsh, is an Australian citizen. Because Australia ratified the Rome Statute back in 2002, the ICC has jurisdiction to prosecute Australian nationals, including Hindmarsh. This is significant because, unlike the Jordanian contingent, the Emirates are reportedly steering the bulk of the ground operation in Yemen.

There is much still for journalists to help uncover about the specifics of Emirati Presidential Guard’s operations in Yemen and about Hindmarsh’s role. But what is known is that the Presidential Guard brings together several UAE armed forces units that operate across land, air and sea, as well as a well-funded special operations unit. Hodeida is the last major port in Yemen that is not under the UAE’s control, and any effort at seizing the port would require the strong involvement of the Emirati forces stationed to the south of Hodeida under Hindmarsh’s command.

From the vantage of The Hague, an investigation of war crimes in Yemen could play in favor of the ICC’s institutional objectives. While the Office of the Prosecutor has historically been unwilling to offend the interests of Western powers, this dynamic may be changing. Facing the threatened mass withdrawal of African states, and having persistently failed to fend off charges of being “anti-Africa” and/or beholden to Western powers, it is an opportune moment for the ICC to be considering a situation like Yemen.

Nonetheless, an investigation of Hindmarsh, or other foreign nationals employed by the UAE, would require the Office of the Prosecutor to break new ground. There is no question the ICC has personal jurisdiction over the nationals of states that have joined the court. But so far the Office of the Prosecutor has shied away from investigating situations that would require it to rely solely on this form of jurisdiction. For example, it did not open a proposed preliminary examination into the Prime Minister of Thailand who the court would have had jurisdiction over solely on account of his dual citizenship with ICC member state, the U.K. Nor did it look into an Israeli officer accused of war crimes who the court would have had jurisdiction over solely on account of his dual citizenship with ICC member state South Africa. In fact, the only instance in which the Office of the Prosecutor has opened a preliminary examination that relies solely on personal jurisdiction has been when the state that forms the basis for personal jurisdiction is also a party to the conflict, as was the case with the Prosecutor’s preliminary examination into allegations against U.K. soldiers in Iraq.

The Prosecutor’s decision on whether to open a preliminary examination based solely on personal jurisdiction, should all other requirements be met, is a prudential one. The Prosecutor has the authority to act but may chose not to do so for fear that her office will be accused of inappropriate discrimination – investigating nationals from ICC member states while nationals from non-member states may be playing an even more culpable role in the very same conflict. But there is also a related legal barrier to such an investigation proceeding beyond a preliminary examination, namely admissibility.

Article 17 of the ICC Statute prohibits the Court from admitting a case that is “not of sufficient gravity…”. With respect to war crimes, this is read in light of language in Article 8(1) that prioritizes war crimes committed “as part of a plan or policy or as part of a large-scale commission of such crimes.” As professor Meg deGuzman has written about extensively, the concept of gravity is highly ambiguous. But in the Office of the Prosecutor’s preliminary examinations involving situations somewhat analogous to Hindmarsh in Yemen, where the ICC had jurisdiction over only one small slice of a broader conflict, the Prosecutor has concluded that the gravity threshold was not satisfied.

First in Iraq, the Office of the Prosecutor considered opening an investigation into allegations of war crimes committed by U.K. nationals. Like Yemen, Iraq has not ratified the Rome Statute, but because the U.K. has, the ICC had jurisdiction over the subset of crimes allegedly committed by U.K. nationals. Finding that once the crime base was narrowed down to offences allegedly committed by only those nationals, the situation would involve 4-12 victims of willful killing and some instances of inhumane treatment, the Prosecutor concluded that the gravity threshold was not satisfied. (The Prosecutor subsequently re-opened this preliminary examination on the basis of new information, but it has not yet made a decision on whether to move forward).

Second, with respect to the Israeli raid on a flotilla carrying humanitarian aid to the Gaza Strip, the Office of the Prosecutor also considered an investigation but then declined on the grounds of gravity. Part of the problem for the Prosecutor’s office was that, of the eight vessels in the flotilla, the ICC only had jurisdiction over three of them. The Prosecutor concluded that incidents on those three were not enough to satisfy the gravity threshold, although the Pre-Trial Chamber disagreed and has since requested the Prosecutor to reconsider her decision. Academics have proposed arguments to the effect that the Prosecutor should consider the entire situation when adjudicating gravity at this early stage—and not just the crimes associated by ICC member state nationals—but so far she has declined to take that approach.

Most recently, after having been encouraged to pursue foreign nationals from ICC member states who have joined ISIL in Iraq & Syria, the Prosecutor emphasized that the crimes committed by those nationals would have to exceed the ICC’s gravity threshold. Explaining that the evidence before her suggested that few nationals from ICC member states occupied ISIL leadership positions, she declined to pursue the matter.

Still, these hurdles may not be insurmountable with respect to the situation in Yemen given the extent of the UAE’s use of foreign nationals. Hindmarsh, as commander of the elite Presidential Guard, is a high-profile candidate for ICC scrutiny. But there are reportedly “dozens” other Australians working for the UAE military in senior positions. And with money seemingly no object, the Emirates have also managed to recruit nationals from Colombia (in the “hundreds”), France, and the United Kingdom – all parties to the Rome State. At the very least, ICC Prosecutor Fatou Bensouda could issue a statement to indicate that her office will monitor the role of nationals from ICC member states in the conflict in Yemen to see if the assertion of jurisdiction is appropriate.

In addition to the ICC, there is also the opportunity for national-level prosecutors to exercise jurisdiction over alleged war crimes in Yemen. Australia’s war crimes legislation, for example, is expansive, providing for universal jurisdiction pursuant to Division 268 of Australia’s Criminal Code. Under Division 268, Hindmarsh would be responsible for any war crimes committed by forces under his effective command provided he “knew or, owing to the circumstances at the time, was reckless as to whether the forces were committing or about to commit such offences.”

Proceedings under this provision require the written consent of the Australian Attorney-General. And Australia, just like the U.S. and U.K., has been selling arms to the Saudi-led coalition, so the political dynamics would seem to cut against an investigation. Nonetheless, political winds change and there is no statute of limitations to prevent a future Attorney-General authorizing a Division 268 investigation.

What’s more, to the extent that one accepts the ICRC’s interpretation of Common Article 1 of the Geneva Conventions, Australia has “a duty to take action in order to safeguard compliance with the Geneva Conventions.” Such a duty would be particularly strong in relation to Hindmarsh, who is one of Australia’s most respected and highly decorated soldiers. After serving as Commander of Australia Special Operations, and leading Australian forces in the Middle East, he was made an Officer of the Order of Australia in 2008. The political dynamics behind an assertion of universal jurisdiction are always complex. Yet as Máximo Langer has observed, the disincentives for an executive branch considering such an approach are greatly reduced when the perceived international political costs are low. The investigation of one’s own national reduces these costs to essentially zero. Government attorneys in other countries with nationals serving in the UAE forces may face a similar calculation.

As the Saudis and Emirates consider an operation to take over the Port of Hodeida, the concrete possibility of war crimes investigations against the sizable number of foreign nationals involved may be the best incentive yet for international backers of the coalition to urge restraint.

Photo: Defense Secretary Jim Mattis meets with retired Maj. Gen. Michael Hindmarsh, commander of the United Arab Emirates Presidential Guard, in Abu Dhabi, Feb. 19, 2017. DoD photo by Air Force Tech. Sgt. Brigitte N. Brantley