Meanwhile, President Trump’s hands-off approach has allowed others to set the regional agenda. With Riyadh, Trump squanders U.S. leverage by offering unconditional support to Saudi Arabia. To Tehran, he offers tough talk without any actual plans to compete more effectively in the region. The result? An emboldened Saudi Arabia acts as it sees fit to fill the void. It’s a formula that leaves the Middle East more vulnerable to military conflict, and American troops enmeshed in the middle of complicated fights. From Yemen to Qatar to Lebanon, it’s not clear if this approach serves U.S. interests. In the worst case, it could even drag America into a regional war with Iran.

The crackdown in Saudi Arabia is just one in a series of events that have roiled the Middle East in recent days. Lebanon’s Prime Minister Saad Hariri resigned while visiting the Saudi capital this weekend, citing an assassination plot and criticizing Iran and its Lebanese partner Hezbollah. In response, Saudi Arabia said Lebanon had declared war against it. Meanwhile, a ballistic missile fired from Yemeni territory targeted Riyadh this weekend—a brazen act of aggression no country would accept. Though the missile was shot down, Saudi Arabia called this a possible “act of war,” blamed Iran, and announced it was closing all land, sea, and air travel to Yemen.

The broader context for all of these events is a wider struggle for power and influence among and between the Middle East’s leading countries—Saudi Arabia and Iran, but also Turkey and other Gulf states. These countries have used military, economic, and political support for proxies to project power, as well as media campaigns designed to influence populations and discredit rivals. The dilemma is that each state fears its meddlesome rivals are funding proxies and then does so itself. As a result, conflicts deepen and the region becomes more polarized, less stable, and less secure—and each government can point to the actions of others. The aggregate effect has been profoundly destabilizing, helping to fragment states and allowing groups like the Islamic State to thrive.

With Saudi Arabia in tumult, its internal stability remains a top concern. Global energy markets have already taken notice of the recent arrests, with the price of oil spiking to a two-year high on Monday. Prince Salman has taken down the heads of powerful security institutions—including former Crown Prince Mohammed bin Nayef, a key counterterrorism partner for the United States for decades, and Prince Miteb bin Abdullah, the former head of the Saudi Arabian National Guard—but it remains to be seen whether his moves to sideline potential rivals will create an internal backlash. So far there are no obvious signs of an organized resistance to the crown prince, who has also outlined a plan to reform the economy and press ahead with significant social reforms, such as taming the country’s religious police.

Then there’s Yemen. A ballistic missile targeting Riyadh was a reckless move by the Houthis, who have benefited from Iranian weapons. America should redouble efforts to help interdict Iranian military aid to the Houthis, but closing Yemen’s access to the outside world would make an already terrible humanitarian disaster even worse. Active U.S. engagement is needed, first to help Saudis find a more responsible way to reestablish deterrence, then to make it an American priority to end this war quickly on terms Saudi Arabia can accept.