Where is Yemen headed as Saleh tries to reassert power?

As Yemen enters its ninth month of widespread antigovernment protests, President Ali Abdullah Saleh's attempt to reassert control rather than negotiate with the opposition is pushing the country toward civil war.

While most Yemenis have shown great restraint and persist in their calls for a peaceful transition of power, the recent return of Mr. Saleh after convalescing abroad from a June assassination attempt has emboldened both Saleh loyalists and protesters opposed to his regime.

"Saleh won't quit until the whole country is on fire," declares Aklan Faris, who has defected from the elite Republican Guard run by the president's son. "But by God he has gone too far. It is ayb [shame] to kill women and children. God willing, Saleh and his family will be forced out."

But neither Saleh's government nor the opposition – a diverse movement of tribal leaders, military defectors including Maj. Gen. Ali Mohsen al-Ahmar, and disillusioned youths – appears to have the support or military assets to triumph decisively over the other.

"None of the key protagonists – Presi­dent Saleh and his family, Ali Mohsen, and the al-Ahmar family – are showing signs that they are either willing to back down or able to achieve an unambiguous political or military victory," says Sarah Phillips, a Yemen specialist at the University of Sydney in Australia.

A civil war in Yemen would not be one in which a single group challenges another. It would be multidimensional, and it could have repercussions for the region – most notably Saudi Arabia, which shares an 1,100-mile border with Yemen.

Saudi Arabia is ill-equipped to deal with the kind of humanitarian crisis that would result from a civil war in Yemen, and the conflict could spread to the Saudi provinces of Jizan, Asir, and Najran, which are home to both ethnic Yemenis and religious minorities – some of whom clashed with the Saudi authorities in 2000.

Such a conflict could also heighten the threat of piracy along the Bab al-Mandeb, a strategic strait that is critical to international oil and cargo shipments.

Divided military, divided country

The Republican Guard, the Central Security Service, and the Air Force, all commanded by relatives of the president, have played key roles in maintaining Saleh's tenuous grip on power.

Despite the thousands of antigovernment demonstrators who continue to fill Yemen's streets, Saleh still has a substantial number of supporters both within the military and among the general populace – likely influenced by his extensive patronage networks through which he has long bought support in exchange for cash, jobs, and influence.

However, the increasing level of violence against civilians threatens to erode the cohesiveness of even those military units that remain loyal to the government. Saleh's return to Yemen and the continued resolve of the protesters are driving many of these units to take ever more desperate measures.

"Saleh and those around him know they have nothing to lose," says Mohammad al-Jawfi, an officer attached to the 3rd Armored Division led by Ahmar, Saleh's "iron fist" for decades until his defection this spring. "It is all or nothing for them. They think they can win now that Saleh is back, but he has lost the people. The men who fight for him are fighting for money. What happens when the money runs out?"

But while much of Saleh's support is undoubtedly purchased, some Yemenis genuinely support Saleh out of the fear that chaos will follow his ouster at the hands of taiyanni, as the young protesters are pejoratively called.

"These taiyanni can only offer us more chaos," says Qassim al-Mahyi, who heads a syndicate that trades in khat, the mild stimulant consumed by many Yemenis. "Only Saleh can hold this country together."

While much of the media coverage has focused on Sanaa and northern Yemen, South Yemen – an independent state until Saleh imposed an unpopular reunification in 1990 – is also experiencing widespread unrest.

Even before the outbreak of protests in late January, residents of South Yemen frequently took to the streets to protest what many of them view as Saleh's discriminatory policies. While the country's limited oil and gas wealth is located in the south, the government is dominated by Yemenis from the north.

Many southerners view the current weakness of the Yemeni regime as an opportunity to press their claims for secession – a movement that is now of critical importance to the stability of Yemen.

"As history has shown repeatedly, whenever the grip on power by the central government is loosened through internal conflicts, centrifugal tendencies gain strength," says Alexander Knysh of the University of Michigan. "Many south-erners watch the events in the north with a mixture of disgust and hope: disgust at the depravity, pettiness, and venality of the rulers; and hope that their infighting will serve as a wonderful opportunity for the south to secede from its perceived or real northern 'oppressors.' "

Not all southerners support secession, however, and many would welcome a transitional government that included influential southern political figures.

Al Qaeda: not the only radical Islamists

The elevated levels of instability and the deterioration of the already limited authority of the central government in Yemen have almost certainly benefited a range of radical groups. Elements of Al Qaeda in the Arabian Peninsula (AQAP) and other radical Islamist groups have been most active in the restive south. For example, the southern governorate of Abyan has seen intense fighting between the Yemeni Army and a group calling itself "Ansar al-Shariah."

The United States and Yemen have stepped up cooperation against alleged terrorists in recent months, and on Sept. 30 trumpeted the killing by US drone attack of Yemeni-American cleric Anwar al-Awlaki, blamed for inspiring English-speaking Muslims to engage in terrorism. His tribe has disputed that he is dead, however, saying the remains found at the attack site were not his.

Some say the Saleh government is conflating the threat of AQAP with that of rebellious southerners, who actually are often opposed to radical Islamist ideologies.

"Most of those targeted by the drones today are not members of this so-called AQAP. Instead, these poor people are opponents of the regime based in the south," says Isa Blumi, author of a recent book on Yemen. "Despite numerous examples of 'collateral damage' resulting in the murder of unarmed people and/or those who have a legitimate right to resist the Saleh regime ... the [US] drone campaign has only expanded."

While radical Islamism is a significant threat in Yemen that is exacerbated by instability and increasing levels of poverty, it is not an issue that is at the forefront for many Yemenis. "Al Qaeda is not what worries me," says Sadiq Jirafi, a business owner in Sanaa. "My worry is the economy. People are losing their jobs and businesses are closing. What happens when the people have no money for food or when there is no food left to buy?"

• Mr. Horton has frequently traveled to and written from Yemen over the past decade.