(The Washington Post)

Saudi Arabia’s King Salman elevated his 31-year-old son Wednesday to become crown prince, ousting his nephew in a seismic shift in the royal succession line that could have deep ramifications for the oil-rich monarchy and the broader Middle East.

Since Prince Mohammed bin Salman emerged from obscurity two years ago, his impact has been widely felt in Saudi Arabia and across the region. He is seen as a modernizer of his hidebound kingdom and a champion of its frustrated youth. But he is also a forceful, and some say hotheaded, advocate for Saudi Arabia’s regional dominance who has thrust the country into bitter feuds with neighbors, as well as involvement in a destructive civil war in Yemen.

Because of his youth — and his father’s age (81) — the new crown prince is poised to play a pivotal role in forging the policy and identity of this key U.S. ally and the Arab world’s largest economy. But he also faces numerous obstacles in implementing his vision for a new Saudi Arabia, analysts said.

On Wednesday, after a flurry of royal decrees, Salman replaced Crown Prince Mohammed bin Nayef, who was also relieved of his influential position as interior minister, in which he oversaw security and counterterrorism operations. The new crown prince will become the kingdom’s first deputy prime minister while retaining his control of the Defense Ministry and other portfolios.

The surprise announcement marks the first time since Saudi Arabia’s first ruler, King Abdul Aziz ibn Saud, that a Saudi monarch has designated his son rather than a brother as his heir apparent. And it is only the second time since the kingdom was founded in 1932 that a grandson of ibn Saud has been named crown prince — and its potential future king. The move also consolidates power within King Salman’s family, while weakening the influence of the families of his brothers and their sons.

“The reshuffle marks the first real test of the ruling Al Saud family’s ability to manage the inevitable generational shift from the sons of Ibn Saud, to his grandsons,” Torbjorn Soltvedt, a Middle East analyst at Verisk Maplecroft, a global risk consulting firm, said in a statement.

The change arrives at a critical time for the Sunni-ruled Muslim kingdom as it grapples with the economic fallout from declining oil prices and a costly military campaign it leads against Shiite rebels in neighboring Yemen. The kingdom also is heading a bloc of Arab nations that has begun a controversial campaign to isolate the tiny Persian Gulf nation of Qatar, accusing it of supporting and financing terrorism.

The White House said President Trump congratulated the new crown prince in a phone call Wednesday and “discussed the priority of cutting off all support for terrorists.” It said they also talked about how to resolve the dispute with Qatar and achieve Israeli-Palestinian peace.

The ascension of Mohammed bin Salman, along with other recent appointments by his father, completes a shift to a younger generation of leaders within the ruling family, one that could bring economic and social change to a nation where women are forbidden to drive, cinemas are banned and coffee shops are segregated by gender. The young prince already is promoting a plan to create jobs for women and modernize a society in which nearly two-thirds of the population is younger than 30 and women make up 22 percent of the workforce.

“We’ve seen the shift of power coming for some time, and the steady centralization of power under King Salman and the purview of his son,” said Kristin Smith Diwan, a senior resident scholar at the Arab Gulf States Institute in Washington.

Even as deputy crown prince, Mohammed bin Salman — popularly known as MBS — was given immense powers by his father. As defense minister, he runs the Saudi campaign in Yemen. As the head of an economic council, he has overseen efforts to revamp the kingdom’s energy policies and build a diverse economy that will sustain itself long after the country’s oil reserves have run out.

Most members of the Saudi royal family supported the prince’s ascension, erasing any remote fear of a challenge to the new crown prince. Mohammed bin Nayef himself publicly pledged his loyalty to the new crown prince in a well-choreographed televised moment.

The crown prince’s rise, some analysts said, has been in the works for several months. A series of decrees in April propelled young royals in their 30s into influential diplomatic and national security positions while undermining Mohammed bin Nayef’s power. Together, the appointments represent a generational makeover of a system once dominated by much older and more experienced royals.

“This new generation’s loyalty is by all accounts to the rising prince,” Joseph Bahout, an analyst at the Carnegie Endowment’s Middle East Program, wrote in a May post.

Since his father came to power in January 2015, Mohammed bin Salman has been brash, outspoken and ambitious. Unlike many Saudi princes who attended elite Western universities, the crown prince was educated in Saudi Arabia and does not speak English fluently. He favors wearing sandals over loafers. But his homegrown credentials have made him popular among many Saudis, especially younger ones.

“He is said to allow his views to be challenged — but does not change them,” Simon Henderson, a Middle East expert at the Washington Institute for Near East Policy, wrote on the group’s website. “His greatest strength, or weakness, may be his ruthlessness.”

Today, he has the ear of his father and the kingdom’s business community.

In 2016, he introduced a post-petrodollar plan that included selling off some of the oil giant Saudi Aramco and creating a sovereign wealth fund to rival those of neighboring Qatar and the United Arab Emirates. But the blueprint also brought complaints from a society that has become accustomed to cradle-to-grave largesse from the Saudi state. Among the belt-tightening measures was a cut in subsidies for gasoline and electricity.

The crown prince is the main driver behind Vision 2030, a far-reaching blueprint to overhaul the Saudi economy and society, focused on live concerts, arts festivals and other forms of Western-style entertainment. But such efforts have also brought complaints from conservative Saudis.

Regionally, said Diwan, the crown prince’s rise almost certainly means the continuation of “a more assertive Saudi policy abroad and a strong alliance with the UAE in pursuing those policies.” Both have shared goals of rolling back Iranian influence and taking stronger action against independent political Islamist movements such as the Muslim Brotherhood.

The crown prince is already the kingdom’s primary liaison with the Trump administration, and his ascension is widely expected to improve ties with Washington. Relations were strained under President Barack Obama over Iran and a 2015 nuclear deal.

In Yemen, the crown prince is the architect of the faltering and bloody Saudi military intervention that has led to thousands of civilian deaths. The kingdom’s hard-line stance on Qatar, which the new crown prince backs, is also becoming a point of tension with Washington.

Meanwhile, the prince has been courting Russia, sensing an opportunity to use oil diplomacy to lure Moscow away from Iran.

And assessments of the crown prince as a “reformer,” by the kingdom’s standards, did not mean that he would deviate from policies that have been condemned by human rights advocates as brutal, including mass executions.

“The reality is Prince Mohammed has stood alongside and publicly defended the king as young men have been tortured and executed for peacefully protesting,” said Maya Foa, director of Reprieve, an international human rights group.

Fahim reported from Istanbul. Brian Murphy in Washington contributed to this report.