Today the Senate Foreign Relations Committee is set to consider dueling bills on Saudi Arabia. A bill sponsored by Senator Robert Menendez (D-N.J.), would block arms sales to the Kingdom and in-flight refueling of Saudi aircraft. This largely mirrors a series of measures passed in the House on July 17 to block the sale of billions of dollars of arms to Saudi Arabia and the United Arab Emirates. But in an unusual move, Committee Chairman Jim Risch (R-Idaho) broke comity to put forward his own separate bill focused more narrowly on the killing of journalist Jamal Khashoggi that would merely deny visas to a few Saudi government officials and require that the secretary of state conduct a review of the United States’ relationship with the country. In all likelihood, this is the bill that will advance, allowing the U.S. sales of arms to Saudi Arabia to continue.

This approach may leave U.S. officials exposed to charges of aiding and abetting war crimes for continuing U.S. support of the Saudi-led coalition in Yemen in the face of evidence of repeated serious international humanitarian law violations.

Congressman Ted Lieu has repeatedly raised this concern, most recently on June 12, 2019, at a House Foreign Affairs Committee hearing on the ongoing arms sales from the United States to Saudi Arabia. In the hearing, Rep. Ted Lieu pressed R. Clarke Cooper, Assistant Secretary at the Bureau of Political-Military Affairs in the U.S. Department of State, on whether the arms sales might leave the United States vulnerable to charges of war crimes, pointing to a undisclosed 2016 legal analysis by the State Department that reportedly concluded there was substantial legal risk to Americans assisting the effort. Secretary Cooper dodged the questions. This was not the first time Congressman Lieu raised the issue. He had done so earlier in a 2018 letter – where he asked about an overdue report on military action of Saudi Arabia and its coalition partners in Yemen as well as about the 2016 legal memo. The U.S. Department of State said very little in response, and it refused to provide the memo Lieu requested.

The State Department is probably circumspect because that memo almost certainly exists and, if it tracks international law, it almost certainly says that there is a real danger that U.S. personnel are in danger of aiding and abetting war crimes by participating in the program of U.S. support to the Saudi-led coalition in Yemen. What’s more, if there was a danger that they might have been guilty of war crimes in 2016, that is all the more true in 2019, after three years of ineffectual assurances by the Saudis that they would take greater precautions to avoid civilian deaths. Indeed, other states are beginning to raise related concerns: Last month, a UK court of appeals halted British arms sales to Saudi Arabia on the grounds that the government did not properly consider whether the weapons would be used to commit “serious violations of international humanitarian law.”

Aiding and Abetting War Crimes

The 2016 State Department Memo referred to by Rep. Lieu most likely addresses aiding and abetting war crimes by U.S. officials under international criminal law. Reuters reported in October 2016 that State Department lawyers had considered whether continuing arms sales to the Saudi coalition could expose U.S. officials to charges of aiding and abetting war crimes. As described at length in this forthcoming article, the international law on aiding and abetting remains in flux. The key differences across international courts is that some require “substantial effect” on the perpetration of the crime to establish the actus reus, while others require only the provision of practical or material assistance. And there are several different mens rea standards. The most common mens rea requirement for aiding and abetting a war crime is “knowledge” that one’s conduct assists the commission of the principal crime, but the International Criminal Court and the Special Tribunal for Lebanon have applied heightened tests.

There is a serious danger that the conduct of some U.S. officials meets at least the more relaxed tests for aiding and abetting under international law and perhaps even the more stringent ones. (As with Ryan Goodman’s earlier article on this topic, I do not address possible immunities. I also focus here exclusively on international law. My coauthors and I considered the domestic war crimes statute in two earlier Just Security articles.)

Beginning with the required action (actus reus) for criminal liability: The U.S. provision of assistance has repeatedly been characterized as important to the Saudi coalition’s war effort. The in-air refueling of warplanes participating in the operations (currently halted) would almost certainly meet the “substantial effect” test, and provision of weapons coupled with intelligence may as well. Moreover, forms of aid and assistance that are not inherently criminal can lead to liability, and the substantial effect test may be met even if the assistance provided is not essential to the causal chain leading to the crime. And while “substantial effect” remains a fairly stringent actus reus bar, providing weaponry that would otherwise not be available to combatants might be enough to satisfy that test if the recipients repeatedly commit war crimes using those weapons (presumably that is all the more true if the use of those weapons is coupled with instruction and intelligence from the provider). (The U.S. government relied on the Taylor decision in its supplemental filing before the Military Commissions in setting forth the prosecutor’s claim that Khalid Shaikh Mohammad was subject to aiding and abetting liability under customary international law.)

Next is the mental element (mens rea) for criminal liability: The most appropriate standard here for mens rea is the knowledge standard. Under this standard, the aider and abettor need not share the principal perpetrator’s intent unless the crime is a specific intent crime. (For example, the ICTY appeals judgment in Prosecutor v. Krnojelac concluded that in order for a perpetrator to be held liable for aiding and abetting the crime of persecution, the individual must “be aware not only of the crime whose perpetration he is facilitating but also of the discriminatory intent of the [principal] perpetrators.”) Generally speaking, the aider and abettor need only know that his or her conduct assists the commission of a crime. Today, many years into the war in Yemen and after repeated public reports of war crimes by the Saudi-led coalition even after assurances to the U.S. that Riyadh would take better precautions, U.S. officials playing a decisive role in the program to support the Saudi-led coalition would be hard pressed to dispute that they knew that providing support to the coalition was likely to enable and assist the commission of future war crimes.

Common Article 1 and State Responsibility

In addition to the possibility that U.S. officials might be said to be guilty of aiding and abetting war crimes as a matter of international law, there are other two legal grounds under which the United States—or those working for the U.S. government—would potentially be legally responsible for violations of international humanitarian law committed by the Saudi-led coalition in Yemen.

First, the United States has a duty not only to not to commit war crimes itself, but also not to enable or support war crimes by other states. As explained by me and my coauthors in the Just Security Yemen Crisis Forum in April 2018, Common Article 1 of the Geneva Conventions (“Common” because the article is repeated in all four Conventions) obligates states to “undertake to respect and to ensure respect” for the Geneva Conventions in all circumstances. We concluded in April 2018 that whether the United States had violated its positive obligation under Common Article 1 turned on the adequacy of U.S. mitigation measures. Now, more than a year later, we can conclude with some confidence that those mitigation measures have proven inadequate. Time and again coalition forces have struck civilians and civilian infrastructure—including a direct attack on an MSF Cholera treatment center. While the U.S. has paused aerial refueling, it has continued many other forms of support including arms sales, maintenance of weapons systems, and intelligence sharing.

Participating in the violation of Common Article 1 can amount to a war crime. As my co-authors and I explained in a separate Just Security article, a war crime consists of two key elements: (1) a breach of international humanitarian law (IHL) that is (2) “serious.” A breach of Common Article 1 is a breach of a state’s own IHL obligations, so the first element is clearly met where there is a violation of that article. The only question, then, is whether it is “serious.” Seriousness, in turn, is generally understood to turn on the severity of the consequences. For instance, the International Criminal Tribunal for the Former Yugoslavia found violations serious when “they took the form of serious injury or death caused to civilians.”

A second possible source of legal responsibility is state responsibility doctrine, which we detailed in another article in the 2018 Yemen Crisis Forum. Under Article 16 of the Articles of States Responsibility, a state may be held responsible for aiding or assisting another State in the commission of an internationally wrongful act if: (a) that State does so with knowledge of the circumstances of the internationally wrongful act; and (b) the act would be internationally wrongful if committed by that State. (What constitutes “knowledge” is a matter of some debate. Harriet Moynihan argues that knowledge “means actual or near certain knowledge of specific illegality on the part of the recipient state.” Ryan Goodman and Miles Jackson, on the other hand, note that most states (though not the United States) support the view that mere knowledge of the circumstances is sufficient.) Again, when we first wrote in April 2018, the United States had sought and received assurances that Saudi Arabia would take greater precautions to adhere to humanitarian law. What we concluded then is all the more true today:

“A continuing pattern of IHL violations after the issuance of assurances makes it more likely that the United States has ‘actual or near certain knowledge’ that there will be future IHL violations by the Saudi-led coalition despite assurances to the contrary—and thus that the United States is responsible for aiding and assisting an internationally wrongful act under Article 16.”

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Congressman Lieu is right to keep pressing the administration on this issue, and his colleagues in the Senate should do the same. At a minimum, the Administration should be required to produce a detailed, unclassified legal memo, containing a classified annex if necessary, explaining its position on the legality of the continuing arms sales and other logistical and intelligence support to the Saudi-led coalition under international law. There is no legitimate reason for keeping the legal analysis hidden from Congress and from the American public, especially as legislators decide whether and how to maintain any U.S. support for the Saudi’s war effort. That the Administration may be unable to justify its actions is no excuse.

Image: Yemeni rescue workers carry a victim on a stretcher amid the rubble of a destroyed funeral hall building following reported airstrikes by Saudi-led coalition air-planes on the capital Sanaa on October 8, 2016. Photo by MOHAMMED HUWAIS/AFP/Getty Images