BEIRUT, Lebanon — Not long ago, the crown prince of Saudi Arabia, Mohammed bin Salman, was hailed across the United States as a long-awaited agent of change who was opening up his conservative kingdom by ushering in an era of social and economic reforms.
Tech giants gave him personal tours in Silicon Valley, Hollywood producers considered Saudi projects, and President Trump praised the prince as an indispensable ally in fighting terrorism and blunting Iran’s influence in the region.
Then, Saudi agents killed and dismembered the dissident Saudi writer Jamal Khashoggi in the Saudi Consulate in Istanbul one year ago on Wednesday — dealing a potentially crippling blow to Prince Mohammed’s international image, upending his charm offensive and prompting some international businesses to shun the kingdom.
Now, after recent drone and missile attacks halved the kingdom’s oil production and cut 5 percent of the world’s oil supply, and at a time when the willingness of the United States to intervene on Saudi Arabia’s behalf is in doubt, Prince Mohammed, 34, the kingdom’s de facto ruler, needs allies. But the shadow of Mr. Khashoggi’s killing continues to stalk him.
“Khashoggi is always going to be a stain on Mohammed bin Salman,” said Hala Aldosari, a Saudi scholar and fellow at the M.I.T. Center for International Studies. “It is not going to go away.”
Prince Mohammed has pushed ahead with his social reforms. Women are now allowed to drive and can marry and travel without the express permission of a male relative. The prince is also pursuing plans to sell shares of the kingdom’s oil monopoly, Saudi Aramco.
But Saudi forces remain bogged down in the war in Yemen, and the attacks on the nation’s oil facilities have raised doubts about the kingdom’s defenses.
Once a frequent guest, Prince Mohammed has not set foot in the United States or Europe since the killing. In July, an American law firm, Fein & DelValle, petitioned the International Criminal Court in The Hague to open an investigation into the prince in connection with Mr. Khashoggi’s killing and “other crimes against humanity.”
And some American lawmakers have sought to cut support for the Saudi-led war in Yemen, which has created a human rights catastrophe, with thousands killed and millions pushed to the brink of starvation.
“Please,” Speaker Nancy Pelosi told the broadcaster NPR when asked whether she would support United States military action against Iran in response to the strikes on Saudi oil facilities. “They’re sitting across from the person who chopped up a reporter,” Ms. Pelosi said. “I don’t see any responsibility for us to protect and defend Saudi Arabia.”
Prince Mohammed has ramped up efforts to regain his lost standing, telling “60 Minutes” in an interview broadcast this week that he accepted some responsibility for the killing because it was carried out by Saudi agents and under his watch. He vowed not to repeat his missteps.
“Even prophets made mistakes,” he said in the interview. “The important thing,” he added, “is that we learn from these mistakes and not repeat them.”
The C.I.A. concluded that Prince Mohammed, who oversees even minor issues in Saudi Arabia, had most likely ordered the killing, and the Senate passed a resolution holding him personally responsible for the crime. In the “60 Minutes” interview, the prince denied that he had given the order or that he had any advance knowledge of the plot.
That declaration, however, is unlikely to change perceptions abroad.
Questions about Prince Mohammed’s culpability and the sincerity of his public statements come as he faces some of his greatest challenges since his father, King Salman, ascended to the Saudi throne in 2015 and began delegating enormous power to his relatively young and inexperienced son.
The questions also come as friends and colleagues of Mr. Khashoggi gathered on Wednesday for a moment of “unsilence” outside the Saudi Consulate in Istanbul, timed to mark the exact moment, 1:14 p.m., when the columnist for The Washington Post entered the consulate, never to return.
Mr. Khashoggi’s fiancée, Hatice Cengiz, attended the ceremony, along with Agnès Callamard, the United Nations expert on extrajudicial killings who investigated Mr. Khashoggi’s killing and has called for an international inquiry; and The Post’s owner, Jeff Bezos.
Prince Mohammed’s critics say that he has made few concessions despite broad international denunciation. Saudi jets continue to bomb and kill civilians in Yemen. A number of prominent rights activists are still detained or are on trial in the kingdom.
Advocates have highlighted the case of the rights campaigner Loujain al-Hathloul, who was detained by Saudi security agents and subjected to torture, according to her family. When asked about the case on “60 Minutes,” Prince Mohammed said that, if true, the accusations would be “very heinous,” and he vowed to “personally follow up on this matter.”
But the alleged abuse happened more than a year ago, and Ms. Al-Hathloul’s siblings say she was pressured to make a video denying she had been tortured to secure her release. She refused and remains in detention.
Current and former United States officials have warned Prince Mohammed that he must ensure accountability in the Khashoggi case or risk more damage to his reputation and that of his nation.
While some foreign companies cut ties with Saudi Arabia or scaled back projects after Mr. Khashoggi’s killing, many still maintain ties with the kingdom. Prince Mohammed’s third annual investment conference, the Future Investment Initiative, will open in Riyadh this month and is expected to receive more Western guests than it did last year, when many top names dropped out as news of Mr. Khashoggi’s killing spread.
Among those who plan to attend is Larry Fink, the chief executive of BlackRock, an investment firm, after withdrawing last year. He argued in a post on LinkedIn that business engagement could push the kingdom in the right direction.
“I believe greater economic integration and diversification will help Saudi Arabia build a more modern and sustainable economy and society for all of its citizens,” he wrote. “I also believe that corporate engagement and public dialogue can help with that evolution.”
The United States government has a long history of working with autocrats in the Arab world and elsewhere, with concerns about human rights violations by American partners rarely taking priority over national security and economic interests.
Saudi officials argue that the kingdom’s decades-old relationship with the United States is broad and valuable to both nations — encompassing business, oil policy, security in the Middle East and elsewhere, and the fight against terrorism.
“This is a very complicated Rorschach test of American foreign policy,” Robert Satloff, the executive director of the Washington Institute for Near East Policy, said of American reactions to Prince Mohammed. “There are a lot of different avenues to enter the anti-MBS universe.”
The Saudis, while condemning Mr. Khashoggi’s killing, have criticized the unrelenting global focus on the case as one fueled by partisan politics in the United States and promoted by the kingdom’s regional foes — Iran, Turkey and Qatar.
They have also cast the strikes on two Saudi oil facilities last month as attacks not just on Saudi sovereignty, but on the global economy.
Inside the kingdom, Prince Mohammed is pressing ahead. Last week, Saudi Arabia began offering tourist visas, betting that an influx of foreign visitors would bring in more cash. And it is hosting high-profile entertainment and sporting events aimed at creating jobs and shedding the kingdom’s reputation as hidebound by a hyper-conservative interpretation of Islam.
While the prince has yet to make significant progress in his efforts to regain his standing in Washington, Mr. Satloff did not rule it out in the long term.
“It is still very early,” he said. “What people are looking for is actions. The words are not sufficient.”
Prince Mohammed has vowed that justice would be done, but Saudi officials have refused to cooperate with international investigators, and the trial in Riyadh of 11 suspects in Mr. Khashoggi’s killing has been shrouded in secrecy. Diplomats who have attended trial sessions have been sworn to silence.
One year after the killing, the kingdom still has not revealed the whereabouts of Mr. Khashoggi’s body, which agents cut up after his killing. Ms. Callamard, the United Nations official, said the Saudis have failed to take sufficient steps to address the crime.
“The main moves have been either of a public relations nature, to try to spin the issue, or to ignore the issue altogether,” she said. “I think the expectation has been all along that people will move along and stop focusing on the issue, and that is not happening.”
Speakers at the memorial in Istanbul on Wednesday said that Mr. Khashoggi’s voice against the oppression of dictators was only growing louder with his death.
“If they cannot stop oppressing us, we will not stop resisting,” said Mohamed Soltan, a human rights activist and friend of Mr. Khashoggi’s. “We are smarter, and we are not restricted by the limitations of power, and history is one our side.”