Following the Sept. 11, 2001, attacks, he became pivotal in the hunt for al-Qaeda militants in the kingdom, said Robert Jordan, who served as U.S. ambassador to Saudi Arabia at the time. As King Abdullah battles pneumonia in a Riyadh hospital, Prince Salman is the man next in line to rule the world’s largest oil exporter as sectarian, political and economic turmoil roils the Middle East.

“He knows how to run a very complex organization,” Jordan, who last met Prince Salman in March 2013, said by phone from Dallas. “He knows how to deal with more than one crisis or problem at a time and he knows how to deal with terrorists and subversive threats in a firm manner.”

King Abdullah, born in 1924, has ruled Saudi Arabia since 2005. His illness has brought to the fore speculation about succession in the biggest Arab economy. While the transfer of power to Prince Salman, 79, is clear, what happens next is less certain, putting the monarchy in uncharted territory at a key time in its modern history.

Saudi Arabia is fighting Islamic State as part of the U.S.- led coalition and trying to keep the threat of extremism and the unrest sweeping the Arab world outside its borders. Its rival Iran and Shiite allies are on the rise in the region. Falling oil prices are reducing the money it has to invest.

Regional Impact

“We are very close to a point in time where the kingdom will go into an unprecedented phase of transition,” Kamran Bokhari, adviser for Middle Eastern and South Asian affairs at Texas-based consulting firm Stratfor, said. “If this state that’s carrying the region runs into internal problems then that has great implications for the entire region.”

Prince Salman, minister of defense since 2011, was chosen by Abdullah as his successor a year later.

It’s not sure who Prince Salman would appoint to succeed him, whether it will be his half-brother and Deputy Crown Prince Muqrin, his full brother Ahmed, or someone from the next generation of princes.

Choosing the right successor will be “a very important challenge” for Prince Salman, said Jordan, who served as ambassador in Riyadh from 2001 to 2003.

Security Question

Prince Salman first must deal with security. Delivering the king’s speech yesterday at the Shura Council, an advisory body, he said the kingdom faced challenges from civil wars and sectarian conflicts in the region that “require us to remain vigilant and cautious.”

In an incident highlighting the difficulties Saudi Arabia is facing, three Saudi security personnel were killed this week near the border with Iraq when a gunman blew himself up after he was encircled near a border post.

Relaying the king’s words, Prince Salman told the Shura Council that the kingdom’s rulers have “been able to deal with these crises and to respond to these challenges, making your country a safe oasis in a turbulent environment.” After the session, he reassured the public on the king’s health, the state-run Saudi Press Agency reported yesterday.

During King Abdullah’s reign, the government spent billions to support its allies, including $5 billion to the Egyptian authorities who overthrew President Mohamed Mursi, $3.25 billion for Yemen in 2012, $3 billion for Lebanon’s army and aid for mainly Sunni rebels battling Syrian President Bashar al-Assad.

In 2011, the Saudis also intervened to stabilize neighboring Bahrain after it was rocked by anti-government protests and worked with the U.S. to negotiate an end to almost one year of protests in Yemen.

Riyadh Governor

Prince Salman was born in the Saudi capital on Dec. 31, 1935. He served as the city’s governor for about six decades before the king appointed him crown prince following the death of his brother Prince Nayef.

During his tenure, Riyadh was transformed from a desert oasis into a thriving modern city of 5 million people, with office towers, sprawling villas and malls bulging with designer boutiques and stores selling the latest gadgets.

As governor, Prince Salman was known to be “very accessible,” visiting the sick in the hospital, going to funerals and receiving people to get to know the city better, Saudi political sociologist Khalid al-Dakhil said. He liked to regale visitors with stories about Riyadh, said Jordan.

“He’s also very fond of inquiring of world leaders their opinions of the threats that are out there, the threats to particularly the Middle East and he’s a very intellectually curious person,” said Jordan, who’s now diplomat in residence at Southern Methodist University in Dallas.

Succession Rules

Six monarchs have ruled since the formation of the kingdom in 1932. Abdullah changed the succession rules in 2007 to give an appointed commission of princes, the Allegiance Council, more power to select a new ruler and the new crown prince. The 1992 basic law stipulates that the king must be a son or grandson of the kingdom’s founder, King Abdulaziz Al Saud.

King Abdullah was admitted to the King Abdulaziz Medical City in Riyadh on Dec. 31. He required the temporary insertion of tubes to assist his breathing. The monarch had been due to stay in his desert retreat north of the capital until the end of winter.

If Prince Salman takes over, his choice of crown prince will be influenced by family politics, said Dakhil. Any question about who is in charge ultimately will have an effect on the economy and Saudi society, said Gregory Gause, head of the International Affairs Department at Texas A&M University.

Oil Price

“They’re in a time of falling oil prices, business confidence is already probably less than it would be otherwise,” Gause said by phone from Riyadh. “If you have an uncertain succession that just doubles business worries about” government spending, he added.

The price of Brent crude declined 48 percent last year as the Saudi-led Organization of the Petroleum Exporting Countries resisted calls to cut production.

The question over succession is not going to make a lot of difference to the oil policy of Saudi Arabia, said David Butter, Middle East analyst and associate fellow at foreign policy research group Chatham House in London.

The family, which numbers in the thousands, has grown to such an extent that the informal way of doing business, sitting down and talking to one another, doesn’t work anymore, said Stratfor’s Bokhari, co-author of Political Islam in the Age of Democratization published in 2013.

“You have a lot of people who are potential contenders for the top jobs,” said Bokhari.

Saudi royals know that, whatever happens indoors, the front presented to the outside world must be united, Butter said.

“I assume they’re going to sort it out among themselves,” said Butter. “With a lot of argument behind the scenes.”