Followers of Zaidi Islam, a branch of Shiism, ruled northern Yemen intermittently for centuries before the Yemen Arab Republic was created after a coup in 1962. The Sunni-led government in Sanaa has since marginalized and repressed the Zaidis, who account for 40 percent of Yemen's population. The Zaidis were left to administer their rugged and resource-poor redoubt in northwestern Yemen's Saada province.
In 2004, the al-Houthi tribe, a member of the Zaidi order, rallied Yemen's Shia to reverse decades of subjugation. The tribe led an insurgency from its mountainous territory in the north against Saudi-backed Wahhabi and Salafist tribesmen and the Yemeni military, both of which the al-Houthis believed were encroaching on historically Zaidi territory. Five more bouts of fighting over six years failed to produce any changes on the ground.
Over time, the al-Houthi rebels became an effective insurgent force of more than 10,000 fighters. By the time Yemeni President Ali Abdullah Saleh was deposed in 2011, the al-Houthis were strong enough to exploit the ensuing power vacuum. They captured Saada city, installed a governor and began collecting taxes and directing the local government. They also began to openly contest tribal control of adjacent territory in al-Jawf, Hajja and Amran provinces.
The latest round of violence began in October, when al-Houthi and Salafist fighters clashed in Dammaj in northern Yemen. Many groups and tribes had targeted the al-Houthis over the years, viewing them as a threat to their influence or territory in the north.
The al-Houthis launched a major offensive after Yemen's January National Dialogue Conference, which designated a year to draft a new constitution and proposed dividing the country into six regions. The offensive was intended to pressure Sanaa into bending on important territorial disputes during the constitution-writing process.
The tribe is displeased with the demarcation of its region, Azal, which has no access to the Red Sea, a large population and little in terms of water or natural resources. The al-Houthis claim rights to coastal Hajja province, including the valuable al-Midi port to the north, and al-Jawf province, which is within reach of Yemen's central oil fields. They have also rejected the Azal region's connection to the overcrowded and distant Dhamar province.
Over the course of a month the al-Houthi rebels gained territory in Hajja and al-Jawf, took the town of Kitaf near the Saudi border and forced the Salafists of Dammaj to retreat south to Sanaa. The focus of the offensive was Amran province, which the Ahmar clan (leaders of Yemen's most powerful tribe, the Hashid tribe) has historically dominated and through which the region's largest highway runs to the capital. By early February, the al-Houthis held most of northern Amran province and had expelled the Ahmars from their home district, Khamir. Notably, anti-Ahmar and anti-government tribes, reportedly including supporters of former president Saleh, joined the rebels' military campaign.
The Yemeni government has been unable to divert forces from other regions to reinforce Ali Mohsen al-Ahmar's 310th Brigade, which has been battling the al-Houthi rebels for more than a decade. The Yemeni armed forces are busy containing al Qaeda in the Arabian Peninsula activities, which are spreading from the country's southeast. Meanwhile, southern secessionists are threatening the country's unity, and tribal militants are threatening its infrastructure.
Despite several short-lived government-brokered cease-fires, heavy fighting continues in Amran, and the al-Houthis have been able to acquire large stockpiles of heavy weaponry and armaments left by withdrawing military forces and tribesmen. With rebels closing in on the capital in early June, President Abd Rabboh Mansour Hadi approved airstrikes against al-Houthi positions in Amran for the first time since the fighting resumed in October. By July 10, however, the al-Houthi rebels had taken Amran city itself, including the 310th Brigade's headquarters and armaments within the city.
Hadi announced July 23 that an agreement had been reached to return Amran to state control, but the al-Houthis will remain on the outskirts and will ensure that no threatening forces are allowed to move back into the city. Moreover, their advance, which the Iranians quietly encouraged, has raised concern in Saudi Arabia.
A Proxy War
For Iran, Yemen's Shiite insurgency is an opportunity to distract its rivals in Saudi Arabia and eat up their resources, keeping them from focusing on regional theaters in which Tehran has bigger interests. Tehran can use its support for the Shia in Yemen as leverage during exchanges with Riyadh over sectarian competition in Syria, Bahrain, Lebanon and Iraq. Over the years, Iran has provided the al-Houthi rebels with limited materiel and financial support and has reportedly directed Hezbollah operatives and potentially Quds Force commanders to help train and direct the rebels.
The Saudis are concerned that the violence, or the al-Houthis' ambitions of autonomy, may spill over into Saudi territory. Saudi Arabia is home to a small Shiite population in its mountainous territories in the southwest, and a far larger Shiite population in its oil-rich Eastern province. In fact, when al-Houthi rebels in 2009 showed signs of overwhelming Yemeni forces and carried out small-scale operations in Saudi territory, Riyadh massed troops on the border and initiated serious airstrikes against rebel positions in northern Yemen until the al-Houthis capitulated.
As in the past, Saudi Arabia's ability to contain the al-Houthis depends on its ties to northern Yemen's conservative tribes, which Riyadh has historically supported financially to oppose the Shia. Nevertheless, the Saudis' influence over the tribes has waned, especially since Riyadh denounced the Muslim Brotherhood, effectively alienating the powerful al-Islah opposition group — whose inner circle is dominated by the Ahmar family — and its affiliated tribesmen.
There is also the fear that Saudi aid may find its way into the hands of jihadists in the north, particularly with the Islamic State expanding its influence in the region and threatening to strike in Saudi Arabia. If recent developments are any indication, such as al Qaeda in the Arabian Peninsula's decision to create a unit tasked to combat the al-Houthi rebels and the July 4 jihadist attack on the Wadia border post, Riyadh's fears are well-founded.
With Yemen largely unable to contain the rebel threat and the al-Houthis sitting on the outskirts of the capital, the Saudis could consider a military incursion similar to the one they conducted in 2009. There have been several recent high-level Yemeni-Saudi talks, including a July 8 meeting between Hadi and King Abdullah in Riyadh and a July 23 unannounced visit by Yemeni Defense Minister Muhammad Nasir Ahmad to the kingdom. Riyadh is likely providing selective assistance to the more moderate Salafist fighters in northern Yemen — as it has in the past — to strike back against al-Houthi territorial gains. Nevertheless, the Saudis must take care not to incite the Shia, particularly in Saudi Arabia's own southern territory, or to allow al Qaeda or Islamic State jihadists to fill the security vacuum in northern Yemen that would follow an intervention.
A Fragile Regime
The al-Houthis are unlikely to advance into Sanaa. They recognize the risk of reprisal from the Saudi military, are wary of triggering a nationalist response that unites northern tribesmen against them and are trying not to spread their forces too thin. The al-Houthis will also probably limit the expansion of their operations northward for fear of repeating the mistakes of 2009, when fighting spread too close to the Saudi border.
Nevertheless, the rebels will work to consolidate control in the territory they have captured and to undermine the support of their Sunni rivals, particularly the Ahmar family. The al-Houthis will also work to strengthen their defensive lines in anticipation of limited counterattacks by Yemeni armed forces and of growing jihadist activity. Yemen's leaders may be flexible on some of the al-Houthi rebels' demands regarding border demarcation and autonomy, but they are unlikely to concede on the al-Houthis' overarching desire for greater autonomy.
More important, the al-Houthi offensive comes at an inopportune time for the Yemeni regime. A large share of Sanaa's military forces have been busy combating al Qaeda elements in Shabwa and Abyan provinces since April. The Hadi regime is also struggling to contain secessionist activity in the south after one of the secessionist movement's most prominent leaders escaped from house arrest and vowed to renew the struggle. Within the government and military, supporters of Saleh are increasingly challenging Hadi; coup rumors came out twice in June. Finally, frequent militant attacks on energy infrastructure have hurt oil and natural gas production, and protests have grown over water, fuel and electricity shortages.
Despite Saudi assistance, Yemen's internal pressures have put Hadi's regime in its most fragile state since the 2011 uprising. The regime could be at risk of breaking down in the near future.