But having invested deeply in Crown Prince Mohammed as the main driver of the administration's agenda for the region, and under pressure from allies who support him — notably the leaders of Israel and Egypt — the Trump administration has concluded that it cannot feasibly limit his power, the people familiar with its deliberations said. An activist wearing a Bin Salman maks during a candlelight vigil for Saudi journalist Jamal Khashoggi outside Saudi Arabia's consulate in Istanbul. Credit:AP Instead, the White House has joined governments around the region in weighing what effect the stigma of the Khashoggi killing may have on the crown prince's ability to rule — and what benefit can be extracted from his potential weakness. "Everybody is milking this," said Maha Yahya, director of the Carnegie Middle East Centre in Beirut. With the crown prince now in need of external assistance to rehabilitate himself, she said, "everybody is trying to turn this to their advantage and try to get what they can out of it." For the Trump administration, the people familiar with its thinking said, that means pressuring the crown prince for steps to resolve the Saudi-led blockade of Qatar and the Saudi-led bombing of Yemen.

US Secretary of Defence Jim Mattis and Secretary of State Mike Pompeo have both issued calls for a ceasefire in Yemen as part of that plan. Loading Officials in the Trump administration had discussed proposals like urging King Salman, the 82-year-old father of the crown prince, to appoint a strong prime minister or other senior official to help oversee day-to-day governance or foreign policy, according to the people familiar with the deliberations. But such ideas were quickly discarded, partly because no one would risk taking such a job, or dare appear to counter Crown Prince Mohammed while he controls the Saudi intelligence and security services and has the king's ear. Scholars and diplomats say it is almost inconceivable for him to relinquish his authority in the way that an official in a Western government might accept a reduced role or shared responsibilities. Power in Saudi Arabia's absolute monarchy, they say, adheres to the individual, not the office.

"All power flows from the king," said Bernard Haykel, a scholar at Princeton University who studies the kingdom and has met with Crown Prince Mohammed. "The king delegates power to a person, and it belongs to that person until the king takes it away." If anything, the killing of Khashoggi has only strengthened the crown prince's capacity to intimidate others inside the kingdom, even in his own family, royals and other Saudis said. Many royals already had lost money and influence because of Crown Prince Mohammed's swift rise over the past three years. The damage to their reputations since the Khashoggi killing has compounded their alarm. Crown Prince Mohammed, often known by the initials MBS, had already humiliated or imprisoned seemingly any potential rival among his royal cousins. At an investor conference he sponsored in Riyadh last week he appeared to smile through the Western backlash, and several Western officials with experience in the kingdom said it was naive to think that a new arrangement of advisers could contain him. "If MBS is constrained, he will try to break out," said a Western diplomat who knows him. "And he will become a threat to those he thinks did it to him."

The crown prince's effectiveness in regional politics, however, is a more open question, partly because the Khashoggi killing has caused many in the West to re-evaluate other episodes in his recent past. His 3 1/2-year-long bombing campaign over Yemen has produced only a military stalemate and a humanitarian catastrophe. His decision a year ago to order the arbitrary detention of about 200 of the kingdom's richest businessmen on vague allegations of corruption has driven away many investors. Perhaps strangest, the crown prince briefly kidnapped the prime minister of Lebanon a year ago in a botched gambit to push back against Iran's Lebanese allies. At last week's investor conference, the crown prince himself made a joke of that misstep, laughingly assuring the Lebanese prime minister he could leave Riyadh freely. A growing number of current and former Western officials are now asserting publicly that in light of the Khashoggi killing, those earlier episodes portray the young prince as dangerously aggressive, impulsive and destabilising. If he were damaged, it would be "because institutions and governments abroad no longer want to deal with him," said David H. Rundell, a former chief of mission at the US Embassy in Riyadh who served 15 years in Saudi Arabia.

But the United States and other Western governments have such extensive ties to Saudi Arabia that they are unlikely to walk away, Rundell said, predicting "a newfound caution and willingness to compromise" from the crown prince. One person familiar with the White House deliberations said the administration expected that bipartisan pressure from Congress will force the imposition of some sanctions. But the White House intends to keep the sanctions limited enough to avoid a rupture with Crown Prince Mohammed. For one thing, he remains central to the plans of the president's son-in-law and Middle East adviser, Jared Kushner, including hopes to build an Arab-Israeli alliance against Iran and to pressure the Palestinians into a peace agreement. Two people close to the Saudi royal court said Kushner and Crown Prince Mohammed communicate often, including by text message, and multiple times since Khashoggi's disappearance. A White House spokesman declined to comment about those communications.