The Washington Post just published a joint investigation revealing new details about the extent and nature of U.S. support to the Saudi- and Emirati-led military coalition in Yemen. Using new data from Security Force Monitor, a project of the Columbia Law School Human Rights Institute mapping security forces worldwide, the investigation details how U.S. support to coalition members’ air forces has continued at an astonishing rate and extends more broadly than publicly disclosed, despite a pattern of ongoing abuses directly stemming from the aerial bombing campaign.

During seven years of war, coalition airstrikes have killed nearly 9,000 civilians in Yemen. Human rights groups and the United Nations-mandated Group of Eminent Experts have documented more than 300 airstrikes that are likely war crimes or violations of the laws of war. These strikes have hit hospitals and other medical facilities, markets, a school bus filled with children, and a funeral hall filled with mourners. Independent human rights groups, journalists, and U.N. monitoring bodies have found U.S. weapons used in many of these attacks. And the attacks continued through this year, until the start of a U.N.-brokered truce in April. In late January, human rights investigators found that three coalition attacks killed at least 80 civilians and injured over 150 more. Yet support to members of the Saudi-led coalition continues to flow. To date, military sales approved under the Biden administration have totaled more than $1 billion, notwithstanding President Joe Biden’s pledge to end U.S. support for the war and hold Saudi Arabia accountable for its human rights abuses.

Yet, the investigation found, “a substantial portion of the air raids were carried out by jets developed, maintained and sold by U.S. companies, and by pilots who were trained by the U.S. military.” Given the devastating civilian toll of the war in Yemen, continued U.S. support for the Saudi and Emirati-led war brings into sharp relief the question that many, including members of the U.S. Congress, former and current U.S. government officials, Yemeni human rights advocates, and Yemeni civilians, have asked for years: why has this support continued, largely unchecked?

The Post-Monitor Investigation

The Post-Monitor investigation into U.S. support for this war, which reviewed more than 3,000 publicly available images, news releases, media reports, and videos, reveals a disturbing pattern. Through visual investigations combined with text sources, the Post and Security Force Monitor were able to identify that coalition members had just 39 airstrike-capable squadrons flying the types of aircraft reported as flying in Yemen. (Co-author Tony founded the Monitor, and Priyanka directs the Institute’s Project on Counterterrorism, Armed Conflict and Human Rights.) The investigation further confirmed that 19 of these squadrons did participate in the Yemen war, with more than half of these coming from coalition leaders Saudi Arabia and the U.A.E. Reviewing sales since the start of the coalition bombing campaign in Yemen up until its seven-year anniversary on March 26 of this year, the United States approved contracts for aircraft, munitions, and equipment used by 38 of the 39 airstrike-capable squadrons.

Relying on open-source information from media, military histories, and government and military websites, the Monitor mapped the entire air force of each coalition country, tracking which squadrons flew which types of planes during the war in Yemen. Squadrons are a key organizing unit of air forces around the world. They typically consist of one specific make or model of aircraft (with eight to 24 aircraft per squadron) and have a specific role. For example, an “airstrike squadron” would be made up of aircraft that can conduct airstrikes, whereas a “transport squadron” would be made up of aircraft that can transport soldiers and/or equipment. The Monitor partnered with Mwatana for Human Rights to review Arabic-language media sources, training researchers to use the Monitor’s methodology to research coalition operations in Yemen.

Based on this research, the Monitor found coalition countries have a total of 39 air force squadrons flying the types of planes that were capable of conducting airstrikes in Yemen:  F-15S/SAs, F-16s, F/A-18s Mirage-2000s, Su-24s, Tornados, and Typhoons. A review of public sources, including air force industry magazines, public videos and photographs, and statements from coalition members’ military officials and spokespeople, indicated that at least 19 of these squadrons definitely participated in the war in Yemen.

Two images. The first shows a number of planes lined in a row. A circle highlights the “RBAF” and the Bahraini flag on the tail of one of the planes. Some of the other planes also have this detail. The second image is a table titled, “F-16 Aircraft Database: Royal Bahraini Air Force F-16s.” Above the chart in smaller lettering reads, “Found 38 aircraft, displaying 1-15 [Sorted by USAF FY/n].” The columns are labeled “Aircraft; T/V; Delivered/Current; Local S/N; AF/Unit; Version” One row is circled and the data for that row reads, “90-0033; AC-6; Delivered 111/Current: 111; RBAF 1 TFS; F-16C Block 40E/FC Block 40E”

Left: Video footage of Mohammed bin Zayed, Crown Prince of Abu Dhabi and Deputy Supreme Commander of the United Arab Emirates Armed Forces, visiting Coalition units participating in the war in Yemen, shows multiple tail numbers, including tail number 111 on plane with Bahraini flag and “RBAF” abbreviation for Royal Bahraini Air Force. Right: Screenshot of public database shows Bahraini plane with tail number 111 belongs to 1 Tactical Fighter Squadron abbreviated to “1 TFS.” Image on file with Security Force Monitor.

The Monitor found that 10 of these 19 squadrons belonged to the Royal Saudi Air Force, and made up its entire set of airstrike squadrons. This means that any U.S. military support to a Saudi airstrike squadron, including weapons, spare parts, or other maintenance supplies, would have gone to one of these 10 squadrons. Indeed, the Saudi air force was able to form an entirely new squadron composed of U.S.-supplied aircraft — F-15SA fighter jets — thanks to U.S. military support. When this new squadron became operational in 2018, it was immediately announced that this new fighting unit would join the Saudi and Emirati-led coalition’s airstrike campaign in Yemen, as seen in the news story below.

Two images of small F-15SA planes, one on a runway and the other sitting near an outer building wall. The top photo includes text from Al Arabiya news that translates to “Saudi adds a F-15SA fighting unit to the fighting units participating in the coalition.” The bottom image includes a circle around the number 2901 on the tail of the plane.

“Saudi adds a F-15SA fighting unit to the fighting units participating in the coalition.” Screen capture from Al Arabiya news, a broadcast channel funded by the Saudi government. Video also shows F-15SA plane with tail number 2901. The Scramble database confirms only the 29 Squadron has tail numbers beginning with “29” in the Saudi air force. Video archived with Yemeni Archive by Security Force Monitor.

A complete dataset on units that served in the coalition’s two phases (Operation Decisive Storm and Operation Restoring Hope) can be found at the Security Force Monitor’s platform. While this information is the most comprehensive view of the coalition to date, on its own it is still not enough to connect a specific squadron to a specific airstrike.

Next, the Monitor reviewed more than 900 U.S. contracts and announcements for the sale of planes, weapons, and other equipment approved since the beginning of the war on March 26, 2015, through its seven-year anniversary in March 2022. While U.S. military contracts do not indicate which specific squadrons will receive equipment, they cover the sale of military aircraft and equipment used by specific types of aircraft. Most coalition countries only have two or three squadrons that fly the type of aircraft that could have benefitted from these contracts. For example, a Dec. 17, 2021 contract providing “support of testing avionics systems onboard F-15, F-16, and F-18 aircraft for the Air Force, and the governments of Germany, Taiwan, and Bahrain” could only support one or both of Bahrain’s F-16 squadrons (no Bahraini squadron flies F-15s or F-18s). Because it is not possible to pinpoint which specific squadron benefitted, this sale is described as “likely benefitting” at least one of these squadrons.

The Post further reviewed “more than 1,500 videos, photos, and public statements by the Department of Defense and coalition members since the war began, and found the United States participated in joint exercises with at least 80 percent of squadrons that flew airstrike missions in Yemen.” These included nearly every squadron from Saudi Arabia and the three U.A.E. squadrons confirmed to have flown missions in Yemen.

The investigation maps the large number of U.S. contracts providing military support to coalition countries, and the very small number of air force squadrons that could have benefitted from these contracts. It does not match specific contracts to specific squadrons, as sales announcements do not name specific squadrons that will benefit, only the type of plane or piece of equipment being sold. Nor could it connect U.S. support to particular airstrikes. However, the research reveals the extent of U.S. support to all coalition countries, and brings into sharp relief just how unlikely it is that U.S. support somehow avoided supporting military units implicated in potential war crimes or serious violations of the laws of war. A detailed look at how the Monitor analyzed and connected U.S. sales to coalition squadrons is available here, and can be used for additional research on these and other contracts announced after the seven-year anniversary of the war.

The findings from this investigation track with other analysis on how the United States has facilitated the war in Yemen. Arms industry expert William Hartung writes, “it is hard to overstate the importance of U.S. arms sales, spare parts, and maintenance to the Saudi war machine. The bulk of the Saudi arsenal is made in the U.S.A., including two-thirds of its combat aircraft [and] nearly four dozen attack helicopters.” Bruce Riedel, director of the Brookings Institution’s Intelligence Project, states, “If the United States decided today that it was going to cut off supplies, spare parts, munitions, intelligence, and everything else to the Royal Saudi Air Force, it would be grounded tomorrow.” Other coalition members similarly rely on U.S. maintenance to support their air forces.

Implications of Ongoing U.S. Support

Given the high probability that U.S military contracts supported air force squadrons carrying out airstrikes in Yemen, and extensive documentation of civilian deaths and injuries from airstrikes, this research raises the question: why has the United States continued providing this support? Contracts approved during the seven-year period are ongoing, with the longest-running contract scheduled to end in 2029. Why has the United States continued to sell the coalition planes and equipment that could be used to carry out further human rights abuses in Yemen, including strikes that could be considered war crimes?

On the campaign trail, Biden promised to take a stance against such abuses. “We are going to, in fact, make them pay the price,” he said, “and make them, in fact, the pariah that they are.” He added that his administration would “end the sale of material to the Saudis where they’re going in and murdering children, and they’re murdering innocent people…they have to be held accountable.” Other former government officials, all of whom have now joined the Biden administration in senior roles, similarly wrote in 2018 that the “war in Yemen is a full-blown crisis, and the United States is literally fueling it.” Meanwhile, members of Congress have strenuously objected over the years to U.S. involvement in the war, repeatedly introducing legislation to end U.S. support to the coalition. Most recently, on June 1, more than 50 members introduced a resolution to end intelligence sharing and logistical support, as well as barring any U.S. personnel from accompanying coalition forces without prior congressional authorization.

In fact, despite announcing the end of U.S. support for the war in Yemen on Feb. 4, 2021, the Biden administration continues to sell “defensive” weapons to Riyadh, including air-to-air missiles and missile defense systems. The administration also continues to service Saudi aircraft, provide logistical support, and share intelligence. Now, in what potentially marks a total reversal of his prior human-rights focused stance, Biden reportedly is planning a visit to Saudi Arabia, which now appears to have been postponed to July.  The Post, in originally reporting the planned trip, noted that it was part of a broader administration push to bolster oil production.

As the Post-Monitor investigation shows, U.S. contracts and sales approved by the Biden administration will continue through 2024 to supply parts and equipment to coalition members’ air force squadrons that have participated, or continue to participate, in the war in Yemen, including seven of Saudi Arabia’s 10 aerial attack squadrons. The administration also continues to provide U.S. military support to each of the three Emirati F-16 fighter squadrons known to have participated in the conflict, as well as to sell equipment, including strike jets and various aircraft equipment to other members of the coalition with contracts running through 2029. As the Post investigation notes, because Saudi Arabia and the U.A.E. purchase weapons from the U.S., rather than receiving them as foreign assistance, they sidestep protections under the Leahy Law, which prohibits U.S. support to abusive military units.

Other analysts writing for Just Security have pointed out that continuing such support could re-ignite concerns about the domestic legal basis for such assistance, as well as raise important questions about what the distinction between “offensive” and “defensive” support truly means. As the Post-Monitor investigation reveals, these sales have continued to support coalition air force squadrons responsible for airstrikes in Yemen, including squadrons that almost certainly carried out attacks that appear to constitute war crimes. Though the investigation was not able to identify which squadrons carried out which attacks, it identifies the small number of units capable of carrying them out.

While the Post and Monitor were able to identify a very narrow universe of airstrike squadrons capable of carrying out attacks in Yemen and likely benefitting from U.S. support, the U.S. government itself has the data to further pinpoint which specific aircraft and squadrons carried out specific attacks identified as potential war crimes. In 2019, while providing congressional testimony, General Joseph Votel (who at the time commanded the U.S. military’s Central Command that oversees operations in the region) revealed that the military had access to a database that detailed every airstrike of the war, including the warplane that carried it out, target, munitions used, and a brief description of the attack. “The database’s existence suggests some American officials had more knowledge of which weapons were used and which squadrons participated in airstrikes leading to civilian harm than the public and members of Congress had been told they had,” the Post concluded. However, their Freedom of Investigation Act request to the U.S. Air Force for access to this database was declined, with the Air Force claiming it did not have the records requested.

The investigation also raises anew the question of U.S. liability for aiding and abetting human rights abuses in Yemen, which Ryan Goodman first raised in these pages back in 2016. Goodman unequivocally notes that: “There is no requirement that the accomplice had the purpose or desire to facilitate the underlying offence.” Instead, it is enough that state agencies or officials “knew that such an act would assist, or had the substantial likelihood of assisting, the commission of the underlying offense.”

In the early years of the war, U.S. officials often argued that U.S. assistance helped Saudi Arabia and other coalition members avoid human rights abuses — by providing them with precision-guided munitions (to help them avoid hitting civilian targets), military training (to avoid errors due to incompetence), and intelligence (which could help avoid hitting civilians and civilian objects). These mitigation measures have proven largely ineffective, however, as large-scale attacks resulting in civilian harm continued.

Meanwhile, accountability — including measures to punish responsible officers and commanders in coalition air forces — remains wholly absent. The coalition has proven incapable of holding itself accountable; the Joint Investigations Assessment Team (JIAT),  a coalition entity set up to investigate reports of civilian harm and potential violations of the laws of war, has also failed to carry out credible investigations. A key U.N. independent monitoring mechanism, the Group of Eminent Experts, was ended after the Human Rights Council failed to renew the group’s mandate last October. Not only has the coalition clearly failed to learn from, or even properly investigate, potential war crimes, but its leaders have also made significant efforts to prevent others from doing so, lobbying member states to end the U.N. monitoring mechanism’s mandate. The argument that these potential war crimes are mere mistakes that U.S. assistance could help correct has not held up. Yet the Pentagon continues to maintain that U.S. support helps avert potential abuse. In response to the investigation’s findings, a Pentagon spokesperson replied that “considerable work remains to be done” with respect to the Royal Saudi Armed Forces’ targeting procedures and investigations. It is difficult to know what improvements the U.S. can realistically expect, after seven years of ongoing abuses, including potential war crimes, with no prospects for meaningful investigation on the horizon.

Two years ago, the State Department’s Office of the Inspector General issued a report reviewing how the department had handled approval of arms sales, specifically precision-guided munitions, to Saudi Arabia and the United Arab Emirates. The report concluded that the department had failed to fully assess the risks that certifying these sales would result in civilian harm, as well as to implement mitigation measures to reduce such harm. Just Security authors also found that the Trump administration circumvented U.S. law in multiple ways to carry out these transfers.

While the State Department investigation focused on specific sales, the Post-Monitor investigation widens the lens — showing that the United States may be ignoring crucial, publicly-available information about just how many coalition air force units received U.S. military support, and how it is nearly impossible for units implicated in abuses to have not benefitted from U.S. contracts in some way. Yet, when interviewed by the Post, former State Department officials noted that the sheer volume of military contracts means there is little time to consider human rights concerns in the current vetting process. Given the extent of U.S. support to the Yemen war, and the nature of abuses raised over years, it is high time for the United States to finally spend the time and resources to review whether coalition squadrons that benefitted from U.S. military contracts conducted attacks in Yemen that may constitute war crimes—and to disclose their findings to Congress and the public. A continued failure to do so would ensure that the United States remains complicit in ongoing — and perhaps future — serious human rights abuses in a war that has claimed countless lives, with no accountability.

IMAGE: Rescue workers carry the body of a victim killed by aerial attacks carried out by aircraft of the coalition led by Saudi Arabia targeting a prison in the Houthi stronghold Saadah Province, on January 22, 2022 in Saadah, Yemen. The assault reportedly killed at least 90 prisoners and injured more than 100 others. (Photo by Mohammed Hamoud/Getty Images)