The U.S. has significant interest in maintaining strong relations with Saudi Arabia's de facto ruler, Mohammed bin Salman. Still, President Trump must pressure bin Salman to take greater care to avoid civilian casualties in Yemen.

That need is clear due to the serious humanitarian suffering that has flowed with a Saudi versus Iran proxy war in the Middle Eastern nation. Attempting to restore government control in Yemen, the Saudis and their UAE allies have been battling Houthi rebel formations that are determined on destabilization. Iran, unsurprisingly, is the primary instigator of the chaos.

Nevertheless, Trump should pressure Saudi Arabia to avoid unnecessary civilian suffering. After all, a new United Nations report released on Tuesday notes that "Coalition airstrikes have caused most of the documented civilian casualties. In the past three years, such airstrikes have hit residential areas, markets, funerals, weddings, detention facilities, civilian boats and even medical facilities." And while the report is written by an authority known for its flexible relationship with reality, its concerns are well-documented in this case.

Moreover, they reflect broader American concerns about Saudi Arabia's increasingly capricious airstrike targeting procedures in Yemen. Dissatisfied by their inability to destroy the Houthis, the Saudis and Emiratis have taken off the gloves with increasingly aggressive airstrikes.

Trump must alter that situation.

Reminding Mohammed bin Salman of his friendship and thanking Saudi Arabia for its support on the Syrian civil war and counterterrorism, Trump should now ask bin Salman for a personal favor to take more care in his military campaign. Trump's aggressive counterbalancing of Saudi Arabia's nemesis, Iran, gives him the credibility and political capital to make this request.

In light of Saudi culture, Trump's personal request would demand bin Salman's attention, and we know that request can work: Earlier this year, the U.S. prevented a humanitarian catastrophe by pressuring the Saudi-UAE coalition to avoid a humanitarian crisis during an assault on a Houthi-held port city.

Ultimately, Trump can help save innocent Yemeni lives while also strengthening Saudi Arabia's moral narrative in defeating Yemen's Houthi insurgency. He should pick up the phone to Riyadh.