Both critics and supporters believe that the purge’s mastermind is Crown Prince Mohammed bin Salman. Photograph by Faye Nureldine / AFP / Getty

With the tacit support of President Trump, King Salman of Saudi Arabia and his powerful son launched an unprecedented purge of their own family over the weekend. The major targets were royal brethren who controlled money, the media, or the military. Among the dozens arrested were eleven senior princes, several current or former ministers, the owners of three major television stations, the head of the most important military branch, and one of the wealthiest men in the world, who has been a major shareholder in Citibank, Twentieth Century Fox, Apple, Twitter, and Lyft.

“It’s the equivalent of waking up to find Warren Buffett and the heads of ABC, CBS and NBC have been arrested,” a former U.S. official told me. “It has all the appearances of a coup d’état. Saudi Arabia is rapidly becoming another country. The kingdom has never been this unstable.”

The purge sent shockwaves of fear through the kingdom—one of the world’s two largest producers and exporters of oil—as well as the Middle East, global financial markets, and the international community. The arrests continued on Monday, with no indication when the crackdown might end.

Both critics and supporters believe that the purge’s mastermind is Crown Prince Mohammed bin Salman, who has had a meteoric rise since he was appointed by his father to be defense minister, at the age of twenty-nine, in 2015. He has vowed to modernize the ultra-conservative tribal society. But, to do it, he has grabbed all the major economic, political, security, and royal court portfolios. In June, he was instrumental in ousting the former Crown Prince—Prince Nayef, a senior royal and the closest U.S. ally inside the monarchy—to become next in line to the throne. (Nayef is still under house arrest, according to Human Rights Watch.) In September, Crown Prince Mohammed orchestrated the arrest of well-known intellectuals and clerics.

On Saturday, King Salman created a new Anti-Corruption Commission and put M.B.S.—as his third son is commonly known, by his initials—in charge. The arrests, in a late-night blitz, soon followed.

“It’s an interesting form of dictatorship that is being created in Saudi Arabia,” Jamal Khashoggi, a prominent Saudi columnist and former editor and adviser to Saudi diplomats who is now in exile, told me. “M.B.S. is now becoming the supreme leader.” Besides North Korea, the only other country where that title is used is Iran, Saudi Arabia’s archrival.*

The arrests are an attempt to consolidate the Crown Prince’s powers, possibly in the run-up to a move by the aged and ailing king to step aside, experts say. The father-and-son duo have already created a whole new royal family that bypassed hundreds (at least) of other princes. “The ruling House of Saud and the entire world now knows that Crown Prince Mohammed bin Salman is ready to resort to any means to consolidate his bid to take over upon the death or abdication of his eighty-one-year-old father, King Salman,” David Ottaway, a fellow at the Woodrow Wilson Center, in Washington, said in a statement e-mailed to me. “Nothing like this has ever happened before in the history of Saudi Arabia, giving the sense the kingdom is entering into unchartered waters with unknown consequences.”

The Crown Prince is also empowered to seize assets and issue travel bans. The Times reported that all members of the sprawling Saudi royal family were also barred from leaving the country. Ibn Saud, the founding king of modern Saudi Arabia, had more than forty sons and even more daughters. Their progeny are now estimated to be anywhere from six thousand to fifteen thousand, with Forbes suggesting, in 2010, that the number could be twice that large.

After Ibn Saud’s death, in 1953, the first generation of sons passed the kingship down the line—with the consent of the other brothers. They ruled by consensus. This is no longer the case: a young prince from among the grandsons has now pushed all others aside.

“What is striking is how this has been a methodical process. He’s taken steps, little by little, to insure potential dissent is silenced or put aside or cast away,” Robert Malley, the vice-president for policy at the International Crisis Group and a former National Security Council staffer in the Obama Administration, told me. “No one has been able to stop him. He’s bested his opponents.”

The Trump Administration supports the sweeping changes that have redefined the kingdom—and the royal family—over the past two years. En route to Asia, just hours before the purge on Saturday, the President spoke with the king from Air Force One to praise him and the Crown Prince for making statements on “the need to build a moderate, peaceful, and tolerant region,” which is “essential to ensuring a hopeful future for the Saudi people, to curtailing terrorist funding, and to defeating radical ideology—once and for all—so the world can be safe from its evil,” the White House reported in an unusually detailed statement.

Trump also said that he is personally trying to convince the kingdom to list the first offering of shares in Aramco—one of the world’s most important oil companies—on the New York Stock Exchange or Nasdaq. “It will be perhaps the biggest going-public ever,” Trump told the reporters flying with him. “Right now they’re not looking at it, because of litigation, risk and other risk, which is very sad.”

Trump did not mention the risk involved in listing the shares in the U.S., but they include the prospect that any Saudi assets in the United States could be seized as a result of the Justice Against Sponsors of Terrorism Act (JASTA) passed by Congress, in 2016. It allowed the families of 9/11 victims to pursue a civil suit against Saudi Arabia—in a lower-Manhattan court—for alleged involvement in the plot. If there is a verdict against the kingdom, the law would also allow a judge to freeze the kingdom’s assets in the United States to pay for any penalties that the court awards.

“That means Saudi Arabia would be extremely vulnerable for listings on the New York Stock Exchange,” Bruce Riedel, a former C.I.A., Pentagon, and National Security Council staffer, told me. “And they know that.”

Ironically, Trump supported the JASTA bill—and condemned President Obama for vetoing it. “Obama’s veto of the Justice against Sponsors of Terrorism Act is shameful and will go down as one of the low points of his Presidency,” Trump said, during the campaign. Congress overturned Obama’s veto—the only time Congress ever overrode him, and in his final months in office. Trump is now critical of the bill.

As part of its lobbying efforts against the bill, Saudi Arabia spent more than a quarter of a million dollars at Trump’s new hotel in Washington—for lodging, catering, and parking—the Wall Street Journal reported in June. The lobbying included bringing in military veterans to speak on the Hill against the JASTA legislation.

The Trump Administration has heavily courted the House of Saud; Trump’s first foreign trip was to Saudi Arabia. Jared Kushner, Trump’s son-in-law, made an unannounced trip to the desert kingdom in late October—his third this year. Officially, the focus was the Middle East peace process, but he has developed a close relationship with the Saudi Crown Prince. (Both are in their thirties.) The royal family’s close ties to the Trump Administration have evidently made the king and his son feel comfortable about taking tough actions against their own people.

The sequence of purges reflects the Crown Prince’s vulnerabilities, as well as his growing powers, partly because his dramatic plans to transform the ultra-conservative kingdom and heighten the Saudi presence across the region are in trouble. His ambitious game plan for the kingdom is Vision 2030, which is designed to shed the country’s image as an oil-dependent state. But not everyone in the royal family stands behind the Crown Prince, who is now only thirty-two years old in a system famed for its geriatric leaders.