COLLEGE STATION, Tex. — It’s been more than a week since the Saudi journalist Jamal Khashoggi disappeared from the consulate of Saudi Arabia in Istanbul, and it’s still not clear what happened to him. What is clear, however, is that the official Saudi story that he left the building freely isn’t believable.

Whatever occurred, it’s also clear that the Khashoggi affair is just the latest sign of Saudi Arabia’s growing recklessness under the leadership of Crown Prince Mohammed bin Salman. Yet more chaos is the last thing the Middle East needs, and it hardly serves America’s objectives in the region.

The Saudi-American relationship has never been based on shared political values. Since it began in earnest in the 1930s, it has been driven by oil and security, and so also by a desire for some measure of stability in the Middle East. Each side has at times strayed from that core goal, notably, in the case of the United States, with the 2003 Iraq War. Yet both Washington and Riyadh have generally preferred maintaining a degree of quiet in the region, if only because that kept the oil flowing and challengers to the American order — the Soviet Union, Iran, Saddam Hussein — at bay. But Saudi foreign policy now threatens that common interest: M.B.S., as the crown prince is known, is a disrupter.

When he first aimed those impulses at shaking up Saudi domestic politics — disempowering the religious establishment, permitting women to drive, opening up Saudi social life, moving the economy away from its overdependence on oil — M.B.S. won plaudits in the West. But when it comes to foreign policy, his approach has failed and it’s dangerous.