Saudi Arabia’s much-discussed Crown Prince Mohammed bin Salman is coming to America this week. Washington policymakers are likely to praise the future king’s much-marketed economic reform plans and pundits will likely speculate on how his stance on Iran will impact American diplomacy. What is less likely to be examined in meeting rooms or on the nightly news is what he’s done in Yemen.

Mohammed bin Salman is not only the crown prince of Saudi Arabia: He is also its defense minister. He oversees all Saudi military forces, according to the defense ministry website; and he has served as the commander of the international coalition in the “Decisive Storm” operation—the coalition operating in Yemen—since March 26, 2015.

Click to expand Image Saudi-led coalition aircraft struck three apartment buildings in Sanaa on August 25, 2017, killing at least 16 civilians, including seven children, and wounding another 17, including eight children. After an international outcry, the coalition admitted to carrying out the attack, but provided no details on the coalition members involved in the attack. © 2017 Mohammed al-Mekhlafi

In March 2015, the Saudis and their Sunni allies in the region attacked the Iran-backed Houthi armed group that then controlled most of Yemen. In the nearly three years since, that coalition, with U.S. support, has continuously bombarded the country with airstrikes that have killed or wounded thousands of civilians in violation of the laws of war. It’s also imposed a blockade that has worsened Yemen’s already precarious humanitarian situation.

Each time I’ve visited Yemen, I am struck by how little the parties to the conflict have done to mitigate the suffering they are responsible for, and how their allies, including the U.S., ignore the relentless abuses exacerbating the world’s worst humanitarian crisis.

The Houthis, too, deserve their share of blame, but it is the Saudi crown prince the United States is welcoming.

The U.S. can use this visit to try to put a stop to the coalition’s many abuses. If President Donald Trump won’t, Congress should.

Last month, I traveled to Yemen’s southern port city of Aden. While Saudi Arabia continues to restrict access to the Houthi-controlled north – where airstrikes are being conducted – the Yemeni government has allowed some access to territory under its control.

Aden has seen much hardship during this war – fighting, frequent fuel crises, an array of newly empowered armed groups, arbitrary arrests and enforced disappearances. The city is now also home to thousands of people displaced from fighting on Yemen’s western coast. Men and women are desperately seeking medical treatment for their wounded children or looking for ways to feed their families. Some told me they brought their children to Aden because they didn’t know how to protect them from fighting elsewhere.

Repeatedly, people said they’d fled their homes because they saw a market bombed, a house hit, a neighbor’s life destroyed after a shell struck. When “the war reached us,” a displaced woman said, the only choice was to flee. When the Houthis controlled an area, other women told us, they feared coalition airstrikes; when the coalition was in control, they feared shelling by the Houthis. Three years into the conflict, no one trusted the coalition or the Houthis to take the necessary steps to protect civilians from harm.

Parents showed me their wounds, and their children’s, but they said that fighters got priority care in the hospitals. And the families I spoke to couldn’t afford to get treatment. No one harmed had received any compensation from the warring parties. And they had no idea if the people responsible for the pain they’d suffered had been investigated.

What was particularly horrible was how familiar stories like these had become.

Millions are now facing hunger and disease. But wartime famine and cholera are not inevitable. Certain individuals are behind the abuses and have the power to curtail them and minimize harm to civilians. If they don’t, they should be held accountable for what they’ve done.

This includes Prince Mohammed bin Salman.

The United States has supported Saudi Arabia in the Yemen conflict from the very beginning. During the Obama administration, the U.S. provided intelligence and aerial refueling for air attacks, as well as bombs and materiel. It did this even after it became clear that many airstrikes were being carried out without regard for the laws of war that prohibit deliberate or indiscriminate attacks against civilians, laws which the Saudis have acknowledged.

Relatives in one village told me how they’d pooled their money to build a well, which coalition aircraft destroyed in late 2016, killing and wounding dozens of men and boys. About a month later, the coalition bombed a prison compound. A child locked up by the Houthis for a minor offense shivered from burn wounds as he described his fear as the bombs fell. In the rubble of these attacks, we found the remnants of U.S.-origin munitions – including one produced months after coalition violations had become clear.

When Donald Trump took office, he could have acted to stop the weapons flow. But instead he used his first trip abroad as president to announce what was billed as the biggest bundle of U.S. weapons sales to Saudi Arabia yet. Since then, the coalition has continued bombing homes, shops and markets – killing and wounding dozens, including many more children.

President Trump should recognize that by selling arms to a military force that is likely to use them unlawfully, he is putting U.S. officials at risk of aiding and abetting war crimes. He should use the crown prince’s trip to change course, making clear that arms sales will stop until abuses do.

The U.S. Congress has not remained silent in the face of mounting Saudi atrocities in Yemen. Nearly half the Senate voted to block an arms sale to Saudi Arabia last year. This month, two separate bills raise concerns about U.S. involvement in the war.

With Mohammed bin Salman’s visit, Congress should step up, even if Trump doesn’t, and remind the crown prince that he cannot wipe his hands of Yemen’s horrors. He should take concrete steps to stop the violations, transparently, credibly and impartially investigate past abuses, and compensate civilian victims.

Millions of Yemeni civilians deserve, at long last, to have their lives treated as they should have been all along: valuable, precious and worth protecting.

Crown princes should not escape accountability.