Saudi Arabia’s U.S.-backed military campaign in Yemen, now almost three years old, not only drives the world’s worst humanitarian crisis, but also deepens the terrorist threat to the United States.

After more than 1,000 days of war, 22 million Yemenis – more than the population of Florida – need international aid, with over a third of those on the verge of starvation. The worst cholera outbreak in modern history has infected more than one million in just nine months, and on average five children are killed or injured each day from fighting, shortages, or disease. After a year of U.S. support for Saudi Arabia – including arms sales, refueling Saudi aircraft, and intelligence-sharing – the Trump Administration finally has begun to question the direction the conflict is headed.

Ending a humanitarian crisis of this scale is reason enough to ramp up U.S. diplomatic leadership on Yemen.  But the country’s connection with international terrorism also demands a renewed American push to end the war.  It was in Yemen that al Qaeda bombed the USS Cole in 2000, killing 17 U.S. sailors, and Yemen-based al Qaeda in the Arabian Peninsula (AQAP) has sought to blow up American airliners, including the failed 2009 “underwear bomber” attack.   More recently, ISIS has established a growing presence in Yemen.

U.S. airstrikes against terrorist targets in Yemen have failed to diminish the threat.  When AQAP’s forces are damaged, ISIS often fills the void. The intense Saudi bombardment of Yemen – since March 2015 a stunning average of one airstrike every 94 minutes – has neither brought Riyadh closer to achieving its objectives nor done anything to alleviate the terrorism problem.  In fact, the Houthi forces, who are the principal targets of Saudi attacks, have been among the staunchest Yemeni opponents of the Sunni extremists in AQAP and ISIS.  Meanwhile, there are reports of AQAP fighters engaged alongside Saudi-supported Yemeni forces, combating the Houthis.

As we should have learned in Afghanistan and Iraq, neither we nor Saudi Arabia can bomb our way to victory.  Extremists prosper in ungoverned spaces and amid war’s misery and deprivation.  As long as the Yemen war drags on, civilians will suffer and the terrorist threat to the United States will increase.  The collapse of government institutions amid three years of war has created openings for AQAP and ISIS to recruit and even to control territory.

The civilian casualties from the Saudi campaign and U.S.-Saudi ties risk creating a generation of Yemeni civilians who see the United States as an enemy.  In Yemen, America’s humanitarian and counterterrorist interests align, because both require a political resolution of the conflict.  Unless the fighting stops, the humanitarian situation will further worsen and the recruiting ability of AQAP and ISIS will continue to increase.

The Trump Administration took an important first step in December, calling out Saudi Arabia for the humanitarian impact of its policies and demanding an end to a Saudi blockade of Yemen’s ports that prevented essential fuel, food, and medicine from reaching civilians.  Congress is increasingly focused on whether U.S. support for the Saudi air campaign is in America’s interests, and is questioning the legality of the Saudi blockade.

But to save the lives of millions of Yemeni civilians and to roll back gains made by AQAP and ISIS, President Trump needs to assert U.S. leadership in securing an end to the conflict.  This will necessitate getting Saudi Arabia to accept that negotiations are the only way to achieve the stability in Yemen that Riyadh has failed to win on the battlefield.

Although UN-led negotiations have been stalled for over a year, the announcement this month of a new UN envoy provides an opportunity for diplomatic progress.  A new UN Security Council resolution could set the stage for resumed peace talks, which neighboring Oman already has offered to host.  Following repeated ceasefire calls by the White House, the Administration should make clear to its Saudi and Emirati allies – including during visits to Washington by Saudi Crown Prince Mohammed bin Salman, and UAE Crown Prince Mohammed bin Zayed – that continued airstrikes will result in the withholding of U.S. military assistance.

Otherwise, Yemen’s war will continue to threaten not only the lives of millions of Yemenis, but also those of Americans as well.

Image: Ibrahem Qasim via Wikimedia Commons.