Portside

In the early hours of Oct. 13, the American military carried out its first direct action against Houthi targets in Yemen, firing cruise missiles that destroyed three coastal radar sites. The strike was retaliation for two failed missile attacks on a U.S. Navy destroyer days earlier.

The Houthis presumably targeted the United States because of its support for Saudi Arabia, which has been bombing Houthi rebels and their allies in Yemen since March 2015.

Tensions in the region, already high, had been escalating for nearly a week. On Oct. 8, warplanes from a Saudi-led coalition bombed a funeral gathering in Yemen’s capital, killing at least 140 people and wounding hundreds of others in the deadliest attack since the start of the war. Two days later, United Nations Secretary General Ban Ki-moon called for an international investigation into whether the attack, which targeted the funeral of the father of a leading Houthi politician, was a war crime.

But the Saudi coalition is not the only party in Yemen facing scrutiny for potential war crimes. The funeral attack has refocused attention on the United States’ deepening involvement in the Riyadh-led war. In addition to providing intelligence assistance and refueling support, Washington has rushed billions of dollars worth in smart bombs and spare parts to help the Saudi air force continue its bombing campaign.

After the attack on the funeral hall, President Barack Obama’s administration pledged to conduct “an immediate review” of its logistical support for the Saudi coalition. National Security Council spokesman Ned Price said the administration was “deeply disturbed” by the attack, and was prepared to adjust its level of support. He added, “U.S. security cooperation with Saudi Arabia is not a blank check.”

Some U.S. officials were already worried that American support to the Saudis – especially assistance in identifying targets and mid-air refueling for Saudi aircraft – would make Washington a co-belligerent in the war under international law. That means the United States could be implicated in war crimes and U.S. personnel could, in theory, be exposed to international prosecution. U.S. administration officials debated internally for months last year about whether to go ahead with arms sales to Saudi Arabia in light of the rising civilian death toll in Yemen.

The United States and other Western powers have not heeded previous international criticism of Saudi actions in Yemen. In August, the State Department approved a $1.15 billion deal for the Saudi military to buy 153 Abrams tanks, hundreds of machine guns and assorted other weapons, many of which are intended to replace machinery destroyed during the Yemen war. (In the same month as the arms deal, the Saudi coalition bombed a Yemeni school, a hospital run by Doctors Without Borders and a potato-chip factory, killing more than 40 civilians.) It was the latest in a series of arms sales by Washington – and, to a lesser extent, Britain and France – to the kingdom since it launched its war, which Saudi officials say is intended to restore President Abd-Rabbu Mansour Hadi, who was ousted by the Houthis and their allies in 2014.

The conflict in Yemen is complex, with a shifting set of alliances: The Shi’ite Houthi rebels are allied with Ali Abdullah Saleh, the ex-president who was ousted after the Arab uprisings of 2011 spread to Yemen, as well as elements of Yemen’s military and security forces who remain loyal to the former president. Saleh was a longtime Saudi ally, who had fought multiple wars with the Houthis. Hadi replaced Saleh in 2012 under a deal brokered by Riyadh.

By late 2014, the Houthis and their allies took control of most of Yemen, and Saudi leaders accused them of being Iranian proxies who were threatening the kingdom’s southern border. At the start of the war, the Houthis’ connection to Iran was tenuous, although there are now reports of closer cooperation with Tehran.

Today, the war is creating more extremism, allowing militants affiliated with Islamic State and Al Qaeda in the Arabian Peninsula – the most dangerous of al Qaeda’s offshoots – to establish new safe havens.

The tension over Saudi actions in Yemen is part of a wider conflict between Washington and Riyadh. The Saudis believe that the Obama administration has abandoned its traditional allies in the Arab world, especially the kingdom and other Gulf states, in favor of a pivot toward Iran. The Saudis were particularly dismayed by last year’s nuclear deal between Iran and major world powers, which lifted economic sanctions on Tehran.

To ease Saudi concerns over Iran, the Obama administration has dramatically ramped up arms sales to Riyadh and other Arab allies in the Gulf. Since 2010, Obama has authorized a record $110 billion in U.S. military sales to Saudi Arabia, according to the Congressional Research Service. The planned sales include dozens of advanced F-15 fighter jets, Apache attack helicopters, naval vessels, missile defense systems and hundreds of armored vehicles.

While Saudi leaders criticize Obama for “abandoning” his traditional allies in the Middle East, and shifting U.S. foreign policy toward Iran, his administration has sold more weapons to the kingdom than any previous U.S. president.

Last month, U.S.-Saudi tensions escalated after Congress voted overwhelmingly to override an Obama veto of a new law enabling the relatives of those killed in the Sept. 11, 2001 terrorist attacks to sue the Saudi government in American courts. The law would lift sovereign immunity and allow the Saudi leadership to be held responsible for the attacks, if victims’ families can prove that Saudi officials played a role in the plot.

More broadly, the kingdom’s increased military spending – and willingness to publicly express anger at U.S. leaders – reflect a more aggressive Saudi foreign policy being spearheaded by the new King Salman and his inner circle. For decades, Saudi Arabia pursued a largely behind-the-scenes foreign policy that benefited from economic expansion fueled by booming oil prices.

The former Saudi King Abdullah, who died in January 2015 after two decades in power, presided over a proxy war with the kingdom’s regional rival, Iran – a series of battles in Iraq, Syria, Yemen, Bahrain and Lebanon – that have shaped the Middle East since the George W. Bush administration invaded Iraq in 2003.

Instead of relying on U.S. military intervention and battling Iran through proxies, Salman and his advisers are upending the old regional order. Salman appointed his 30-year-old son as defense minister, and deputy crown prince, to oversee the Yemen campaign. The war is popular with the Saudi public, despite the economic cost and mounting civilian casualties in Yemen. In late August, the United Nations estimated that the war had killed at least 10,000 people and displaced 3 million Yemenis.

Last week’s attack on the funeral in the Yemeni capital should be a turning point for U.S. policy. As the Yemen war grinds on and civilian casualties are mounting, the Obama administration must answer for its support of the Saudi campaign, which is prolonging the conflict. Even if Saudi Arabia balks at ending its air strikes, it can’t keep up the war without U.S. weaponry, intelligence and logistical help. The Obama administration can stop this bloodshed.

[Mohamad Bazzi is a journalism professor at New York University and former Middle East bureau chief at Newsday. He is writing a book on the proxy wars between Saudi Arabia and Iran. @BazziNYU]