Saudis enter the fray

SAUDI Arabia was only going to tolerate the advance of the Iranian-backed Houthi rebels in neighbouring Yemen for so long. Early on the morning of March 26th the kingdom said it had launched a military operation to push back the Houthis and reinstate the “legitimate government” of President Abd Rabbo Mansour Hadi.

Initial airstrikes hit the Shia rebel group's positions in Sana’a, the Yemeni capital, including the airport and the group’s political headquarters. They also targeted military bases controlled by loyalists of Ali Abdullah Saleh, Yemen’s former president. He was ousted in 2011 and subsequently has been backing the Houthis as they have taken over swathes of the desperately poor country of 24m. Later reports suggested bases of Saleh-loyalist military units in the other areas of the country had also been struck.

Adel al-Jubeir, the Saudi ambassador to America, says the strikes are an opening salvo in a campaign involving ten countries—mainly believed to be fellow Gulf states. The White House announced shortly afterwards that America would provide logistical and intelligence support. Jordan and Egypt have offered to take part.

In 2013 the Houthis burst out of their stronghold in northern Yemen and moved south to Sana’a, eventually seizing it in September last year. Last month Mr Hadi, who is backed by both America and the Saudis, fled Houthi captivity in Sana’a for Aden, a port city that was once capital of an independent South Yemen.

By the time the Houthis advanced on Aden this week, after taking an important military installation 60km northwest of the port, Mr Hadi was rumoured to have fled to Riyadh, the Saudi capital. He called for military intervention from the six member-states of the Gulf Co-operation Council.

Saudi Arabia has answered his call. But by leading a military campaign to reinstall Mr Hadi as president, Riyadh may catalyse Yemen’s long-predicted collapse into what Jamal Benomar, the UN envoy to Yemen, has described as an “Iraq-Libya-Syria scenario”.

The Houthis, a religious revivalist group turned militia, are backed by Iran, a Shia power, with which Saudi Arabia, a Sunni bulwark, competes for regional hegemony. The Houthis, like most of Yemen's Shia, follow the Zaydi sect of Islam, as opposed to the "Twelver" form of Shia which predominates in Iran. Nonetheless a Sunni-led intervention is likely to increase sectarian divisions within Yemen—where the distinctions between Sunni and Shia meant little until recently—and to aggravate them regionally.

Militant Sunni groups have already carried out blatantly sectarian attacks. Yemen is home to al-Qaeda in the Arabian Peninsula (AQAP), al-Qaeda’s deadliest branch, and Islamic State (IS), which claimed responsibility for the suicide bombings of two Zaydi mosques in Sana’a on March 20th, which left more than 140 people dead.

The air strikes have already laid bare the divisions caused by the Houthis' rise. In Yemen's south and in the central belt, territories home to mainly Sunni populations, people are cheerleading the Saudi-led campaign. They are hoping it will halt progress of the Houthis, who had looked set to enter oil-rich Mareb, in central Yemen, as well as Aden, until the strikes were launched. The anti-Houthi groups’ interest is not whether or not Mr Hadi—a man who ceded control of the capital without a fight six months ago—has legitimacy; rather that the Houthi menace be brought to heel.

In the north of the country many are dismayed by the foreign bombardment, including some of the Houthis' sternest critics: they believe it will only lead to more fighting. “Saudi Arabia is fucking our country,” says a Sunni tribesman who spent the night cowering with his family in Sana’a as blasts echoed through the capital. Many Yemenis believe Saudi Arabia will happily reduce their country to dust to defeat their enemies.

For the Houthis, the Saudi-led operation is a public-relations coup. They have long accused Mr Hadi of working for the interests of foreign powers. In a vitriolic and paranoid speech on March 20th their leader, Abdelmalek al-Houthi, accused the Gulf Arab states and America of plotting to destabilise the country in order to reinstall Mr Hadi as a puppet leader.

Mr Hadi has struggled to build a constituency since being made interim president in 2012. What support he has found since leaving Sana’a has been based largely on his opposition to the Houthis. From Aden Mr Hadi had been in the process of forming a 20,000-strong Saudi-backed militia. When he went, the country's "legitimate government" left with him.

The Saudis’ campaign may not be easy. The Houthis have evolved into a highly effective guerrilla force after a decade of war against Mr Saleh and Saudi Arabia. With the backing of Saleh loyalists they are likely to prove a tough enemy.

Last time Saudi Arabia intervened against the Houthis in Yemen, it suffered blowback. In response to Saudi airstrikes against the rebels in and around the northern region of Saada, Houthi fighters crossed over the Saudi border, seizing dozens of towns and villages. (Ironically, those strikes were to support the regime of then-president Mr Saleh, which was struggling in its sixth campaign in as many years against the Houthis.)

The Houthis have once again threatened to take the fight across the border. “This will be just like the sixth war in Saada when the Saudis lost Saudi territory,” says a Houthi man in Sana'a, referring to the 2009 offensive. It is not just Yemen that may come to regret the Saudis’ latest foreign adventure.