Saudi King Salman bin Abdulaziz al-Saud, left, at the opening session of the Arab leaders summit last month in Sharm al-Sheikh, Egypt. (European Pressphoto Agency)

— In the two weeks since Saudi Arabia launched a bombing campaign in Yemen, the kingdom has barely slowed the advance of Shiite rebels who appear to be digging in for a long fight.

But so far, Saudi commanders have projected no outward signs of concern that the campaign is falling short.

“We should not be impatient for the results,” Brig. Gen. Ahmad Asseri, the spokesman for the Saudi-led coalition, cautioned on Friday.

Saudi Arabia’s determination is rooted in something deeper than overcoming insecurity on its borders and the fear that rival Iran could take advantage of it through perceived links to the insurgents. Saudi Arabia’s leaders — backed by its powerful Islamic religious establishment — also have taken on a special role as guardian of both its southern neighbor and the wider Arabian Peninsula.

“This is a blessing . . . but it also places a responsibility on all of us,” King Salman told a gathering of the nation’s political and armed forces elite at his Riyadh palace last week.

This was more than just a rallying call by the monarch, a former defense minister who took the throne in January. It also reflected entrenched Saudi views on Yemen, shaped over decades of intervention, insurrection, tribal politics and intrigue. It also reflected a growing military assertiveness by Saudi authorities, who have received a crucial stamp of approval from the influential Sunni religious leadership that gives the royal family legitimacy to rule over the land of Islam’s holiest sites.

In Saudi calculations, the potential costs of the Yemen intervention — even the risks of further deepening regional tensions with Iran — are overshadowed by the historical imperative of keeping Yemen under Saudi wings, experts say.

“Saudi Arabia sees itself as the big brother of Yemen,” said Ali al-Ahmed, director of the Washington-based Institute of Gulf Affairs, which is often critical of Saudi policies. “That — more than Iran, more than trying to reinstate Yemen’s Saudi-friendly president — is at the heart of the decision to launch attacks. If Saudi leaders are not calling the shots in Yemen, they get very nervous.”

And probably at no time since the founding of the modern Saudi state more than 80 years ago has the kingdom been less in control of affairs in Yemen.

Yemen has splintered into a patchwork of fiefdoms dominated by forces hostile to Western-allied Saudi Arabia but which are also fighting each other. These include a powerful branch of al-Qaeda, groups claiming loyalty to the Islamic State and the Shiite rebels known as Houthis, who control the capital, Sanaa, and seek to gain full hold over the second-largest city, Aden.

The immediate goal of the Saudi-led attacks is to restore Yemen’s president, Abed Rabbo Mansour Hadi, who escaped to Saudi Arabia after rebels closed in on his compound in Aden last week. But Saudi Arabia and its Sunni Arab partners also have made clear that longer-term objectives are in motion.

That was reinforced last Sunday with a decision by the Arab League to form a joint rapid-
reaction military force
to respond to regional crises. The move was both a potent message to Shiite power Iran and a sign of greater regional cooperation against threats such as al-Qaeda and the Islamic State.

The stirrings of expanded Arab military resolve already have been on display. Nations including the United Arab Emirates and Jordan have joined U.S.-led airstrikes against the Islamic State in Iraq and Syria. In February, Egyptian warplanes targeted suspected Islamic State cells in Libya.

Nor has Saudi Arabia been idle. The kingdom has been a critical financier for Syrian rebels seeking to topple the Iranian-backed government of Bashar al-Assad.

Yemen, however, presents a new slate, experts say. It could become a test ground for a sustained Saudi-directed offensive that reaches beyond the current Houthi showdown and takes aim at al-Qaeda and others — possibly even eclipsing the Pentagon’s strategy of drone strikes by bringing in greater firepower and ground forces.

“We are seeing the beginnings of the ‘Salman Doctrine,’ ” said Theodore Karasik, a Dubai-based defense analyst specializing in gulf affairs. “It says that Saudi Arabia must take a stand to protect the gulf rulers and the status quo of allied states around the Arab world.”

The coalition spokesman Asseri strongly suggested Thursday that the rebels are not the only aim of the intervention, calling the Houthis and al-Qaeda “both faces of the same coin.”

“One of the goals of the mission is attacking all terror groups,” he said.

There was a preview of Saudi Arabia’s stronger regional military role under Salman’s predecessor, King Abdullah, who answered a call for help from neighboring Bahrain in 2011 by sending in troops to aid the tiny country’s Sunni monarchy, which was facing Shiite-led protests. Yemen is a much bigger stage, with more at stake.

“The Saudis look at Yemen as the soft underbelly of their country,” said Labib Kamhawi, a political analyst based in Amman, Jordan.

In the 1960s, Saudi forces came to the aid of a ruling Shiite dynasty in North Yemen after it was deposed in a coup backed by the pan-Arab nationalist government of Egypt’s Gamal Abdel Nasser. The Saudi fight on the royalist side, ironically, was on behalf of Shiite clans, including some that now back the Houthi cause.

But shifting fortunes and alliances of convenience have been a hallmark of Saudi relations in Yemen. Riyadh eventually reworked its strategy and became a financial and military pipeline for the Egypt-allied government in North Yemen, which then split from Marxist-leaning South Yemen.

Meanwhile, the austere Saudi brand of Islam, known as Wahhabism, gained a greater foothold in Yemen through Saudi-funded mosques and groups. These served as sources of intelligence-gathering and recruitment for local fighters against the Houthi rebels, who remained mostly confined to northern enclaves before a series of stunning gains last year. Saudi money also sought to buy loyalty among both Sunni and Shiite tribal sheiks in Yemen and on the Saudi side of the border, a line that in many places is still not clearly defined.Saudi Arabia became further vested in Yemen through development projects spearheaded by wealthy merchant families with Yemeni ancestral roots.

In 2007, King Abdullah was widely quoted as calling Yemen’s security “inseparable” from that of the kingdom. Two years later, a wanted Saudi-born man who trained with Yemen’s al-Qaeda branch tried to kill Saudi Arabia’s then-deputy interior minister, Mohammed bin Nayef, in a suicide attack. Prince Muhammad was slightly injured and vowed to further increase crackdowns on militants, particularly those linked to al-Qaeda in Yemen.

That was before the Arab Spring again reset the political equations in Yemen.

In 2011, Saudi Arabia threw President Ali Abdullah Saleh a lifeline, allowing him to take refuge and receive medical treatment after he was badly burned in a bombing by Arab Spring-inspired demonstrators at the besieged presidential compound.

Saleh now appears to have cast his lot with the Shiite rebels in a bid for a political resurrection.

This would mean another player, and another layer of complications, even if Saudi Arabia does manage to get the exiled Hadi back in power. The ultimate outcome will likely leave various factions jockeying for influence and undercutting Saudi Arabia’s traditional top position, said Hashem Ahelbarra, an Al Jazeera correspondent who has closely covered Yemen.

“Yemen,” he said, “is never going to be the same again.”

Hugh Naylor in Beirut contributed to this report.

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